Brian Keegan is a regular opinion columnist for Boulder Reporting Lab. His “Charting Boulder” column uses public data to make sense of how the city is changing — from housing and politics to income and population — with clear explanations and a focus on equity.
“Boulder is full!” is a common refrain in debates about Boulder’s land use, housing and transportation policies. Since the 1960s and 1970s, Boulder has enforced strict open space protections, established the “blue line” development boundary and adopted deliberate slow-growth policies aimed at safeguarding natural resources. Decades later, these measures still profoundly influence local discussions, often narrowly focused on limiting population growth.
But is Boulder actually full? By leveraging historical population data published by the State Demography Office as well as other U.S. Census data, we can explore trends in the population of both the city and county of Boulder.
In absolute terms, decennial Census data reveals that Boulder’s population in 2020 was the highest in its history. Beginning in 1970, the population trends of the city and county began to diverge because of the city’s adoption of slow-growth policies.
These policies did little to stop population growth in the rest of the county. In 1960, 50.8% of Boulder County’s population lived in the City of Boulder. By 2020, that share had fallen to 32.7%. This redistribution indicates that growth has migrated toward neighboring communities, reshaping the region’s demographics and urban form.
But Census data are only reported every decade. Annual data since 1980 show that Boulder’s population peaked in 2016. Boulder County also saw its first real declines in population in 2021. These drops are likely temporary, reflecting consequences of the Covid-19 pandemic, the Marshall Fire and higher interest rates.
Nevertheless, population growth in both the city and county are unmistakably slowing: Annual growth in the county hasn’t exceeded 2% since 2001 and 1% since 2016. The State Demography Office forecasts that the county’s population growth will remain below 1% and ultimately will become negative — a shrinking population — by 2050. These trends highlight the urgency to reconsider our current strategies for managing growth.
Boulder’s declining population is also evident when looking at its share of Colorado’s total population. In 1970, 3% of all Coloradans lived in the City of Boulder. By 2020, that number had fallen to 1.8%. The percentage of Coloradans living in Boulder County peaked in 1990 at 6.8% and has since declined to 5.7%.
Making Boulder more accessible by permitting in-fill development or shifting away from car-centered transportation often elicits objections that these are “big city” proposals. Ranking the city over time shows that Boulder was the fifth-largest city in Colorado back in 1960 and by 2020 had declined to the 12th largest. The county has been around the sixth-largest in the state but has since declined to the eighth-largest.
Boulder’s halcyon days — often described as vibrant, affordable and weird — are typically attributed to some time between 1970 and 1990. These rose-tinted memories also correspond to the data above, when Boulder was growing most rapidly and at its fullest. Once upon a time, Boulder welcomed newcomers with housing and jobs, not blame and hostility.
Those who claim “Boulder is full” rarely acknowledge their own role in Boulder’s growth. It’s always someone else — especially the newer arrivals — who are blamed for degrading the environment. In that logic, Boulder became “full” shortly after they moved in.
The causes of Boulder’s decelerating growth are complex, but we continue to confront the consequences, along with groups and policies still committed to keeping Boulder frozen in the past. Seniors struggle to downsize into more accessible housing. Some schools face the threat of closure due to under-enrollment. Sales tax revenue is evaporating, blowing holes in budgets. Choices made 50 years ago are impacting all of our lives today.
Critically, this anxiety about Boulder’s growth hasn’t stopped development: Sprawl has just spilled haphazardly across surrounding communities. Broomfield, Superior, Lafayette, Louisville, Erie, Longmont and Lyons might have enjoyed the short-term high of jobs, fees and tax revenue that come with new development. Now these communities are only beginning to grapple with the long-term costs of sprawl.
Boulder’s open space, blue line and regional planning policies have unambiguously helped to preserve precious natural resources. But population growth and urbanization themselves are not responsible for environmental degradation. Outdated policies that promote inefficient energy and water use alongside car dependence are to blame.
The demand Boulder has ignored in the name of “no growth” has two effects. First, it puts pressure on less-prepared neighboring communities to haphazardly develop their open spaces. Second, it weakens Boulder’s own social and economic vitality by sending families, jobs and tax dollars elsewhere.
Boulder is not full — and it is troublingly poised to become emptier. If we continue attributing environmental harm to scapegoats like population growth, rather than policy decisions, we risk doubling down on ideas that no longer serve us.
As the city and county prepare to revise the Boulder Valley Comprehensive Plan, it’s time to leave its population anxiety in the past and center responsible growth to meet our obligations to future generations.
The data and code for replicating these analyses can be found on GitHub.
Editor’s note: Brian Keegan responded to reader feedback on his June column in a follow-up piece. You can read it here.
Brian- What don’t you understand about balancing jobs and housing?
Exploring the balance between jobs and housing over time is an excellent idea for a future column!
Good food for thought. I arrived in Boulder in 1975 to go to graduate school because I wanted the small town feel.
Welcome, Brian! I look forward to reading more of your work.
I imagine you’ve got some great ideas lined up for your first several columns. But if you’re open to pitches, I’ve been very curious how Boulder would fare on the Strong Towns Finance Decoder (https://www.strongtowns.org/journal/tag/Finance+Decoder) but I’ve been too timid to find the data required and plug it into the spreadsheet.
Looking at trends and patterns with city and county budgets is definitely on the roadmap. I am very open to pitches, keep them coming!
Great commentary and food for thought. Sadly the no growth mindset is expanding to other parts of the county. Nothing you mention surprises me. Have lived in Louisville for 24 years and we are now grappling with same issues. It’s sad that my kids who grew up in Louisville and are working in jobs actually helping people and the environment can’t afford to live or work here due to lack of affordable/ attainable housing. Prices in E county are pushing closer to Boulders and young people, families, seniors etc are being priced out.
I wrote this in 2015.
https://www.boulderblueline.org/?p=15615
It’s obsolete now—someone can live in Boulder and work in Manhattan, virtually. But, maybe you could look at the cost of housing in Boulder and see if you can infer a way to obtain an economically diverse community in a beautiful place.
What Boulder did that is worth emulating is make itself compact; there is an edge to Boulder, not a diffuse fringe of sprawl. How can this be maintained along with an economically diverse community?
Our neighbors on the Boulder street where I grew up covered a broad range of employ and income. And, I could ride my bike to the edge of town. What could we have done differently to have both of those things?
Excellent points. A future column could tracking trends in income and wealth and how Boulder stacks up to other Colorado communities and similar college towns across the country.
Without deeply engaging in the Boulder growth debate, I see some curious truth claims and reasoning in this opinion piece.
“This redistribution indicates that growth has migrated toward neighboring communities . . .” This comment assumes that a person would rather live in Boulder than in a neighboring community, Lafayette, Louisville, Longmont, Erie, Superior, Lyons, etc. Why would you make that assumption?
“Sprawl has just spilled haphazardly across surrounding communities.” I’m sure that residents of these cities will be happy to be informed that they are “haphazard sprawl.”
“It weakens Boulder’s own social and economic vitality by sending families, jobs and tax dollars elsewhere.” Why should the City of Boulder hoard all of this social and economic vitality? Do not other cities deserve a bit of it? Why assume that economic and social vitality can only be directed to Boulder?
“In 1970, 3% of all Coloradans lived in the City of Boulder. By 2020, that number had fallen to 1.8%.” Given that there is much more buildable land in the State of Colorado than there is in the City of Boulder how is this surprising?
All of the percentage of people living in Boulder vs the rest of the area/state was nonsense commentary. As the rest of the area and the state grew, Boulder couldn’t remain the same percentage of state makeup because other non-developed areas naturally were where much of the growth to accommodate the influx of people to the state occurred. Boulder couldn’t grow at that same rate, it was already developed.
Second issue with all of this commentary is the real issue isn’t completely Boulder being ‘full’ from a housing growth perspective, it is that we allowed Google, Apple, etc all to locate here, so influx of traffic has grown substantially. Look at 30th 15 years ago vs today from a development (commercial and residential) perspective and the resulting growth in traffic on it – a fair deal from out of Boulder. Now they want to remove a traffic lane there (and Iris and Folsom).
Finally, the article promised to talk about what is driving people away, but didn’t hit that at all. What is driving them away are these crazy changes to traffic control/mitigation and the lack of tax revenue leading to massively out of what property tax assessments – our ‘proposed’ increase was 33% this year!!! As a person about to retire that is insanity – we are being chased out after 25 years of residency.
BoulderG wrote, “What is driving them away are these crazy changes to traffic control/mitigation “… The changes to 30th, Iris, and Folsom are only planned at this stage. They have not yet occurred. So are you saying that these plans are driving people away? Plans to make the city’s main streets more safe for everyone? As for the (legitimate) complaint about property taxes, the increases are because our houses have become much more valuable. The value is increasing because we have done a good job of making Boulder a good place to live, and rich people move to nice places.
So you are saying property values went up 33% in one year…in line with the tax increase given to me? They put our home $400k over what all of our RE friends say is at all obtainable.
And yes, MANY of the people we have known for decades here are searching out of the area due to what they know is coming because of ill-advised changes. Three families in our circle gone this year already.
Clearly the author has a Boulder – centric outlook.
Brian, it would be interesting to look at census statistics on household size in Boulder and Boulder County over time. I’m speculating that 30 or 40 years ago, homes in Boulder were filled with families with 2 or more children. Today – despite the addition of thousands of housing units downtown, in Boulder Junction, along North Broadway, “filling up” Boulder – population is stagnating or declining because more homes are occupied by 1 or 2 people. It’s unlikely that any government policy – local, state, or federal – could greatly influence that demographic reality.
Excellent points. State Demogapher Elizabeth Garner touched on many of these and related points in her keynote presentation kicking off the BVCP engagement process: https://vimeo.com/1027797187
This column raises good points. As someone looking to move to Boulder, I have been disappointed with the housing options, especially lack of modern condos, and the high cost, even more expensive than where I live in Washington DC. It seems without some level of growth, Boulder will suffer from lower tax revenue, higher costs for many businesses because a lack of staff, and a loss of talent coming into the city in healthcare, education, technology etc. I hope city leaders will find the right balance that ensures a vibrant and growing city that preserves a good quality of life for everyone, including new residents like me.
We share the same concerns!
I believe that the growth and development Boulder has experienced in the past 20 years has not been responsible. The buildings are too high and dense, the architecture ugly and unimaginative, and the new parking plans for Boulder are unrealistic. Who can do a weekly/monthly grocery shopping on a bicycle? If the city wants to encourage new population, then making people pay for a parking space at the condo they are buying or renting will backfire.
Agreed – even if you could shop weekly groceries for a family on a bike, 99% of us aren’t going to do that in the middle of winter! My guess is most/all of the people driving that agenda don’t regularly ride a bike, they are just unrealistic idealists. I do (100 miles/week to work and back) and don’t believe they live in reality.
Brian, thanks for this interesting and thoughtful discussion. I sometimes wonder about how the CU community, and especially the student population, distorts Boulder demographics. About 30% of the census counted population are students. So, we are a city of 80,000 permanent residents and 30,000 itinerant residents. I expect Boulder is richer and older than the combined stats show. I’d be interested in your insights regarding this view of Boulder.
Looking at the CU enrollment patterns is definitely worth exploring in the future.
Its inevitable Boulder goes the way of Aspen, as example, where the desirability of Boulder is its own death nail. The very desirability that draws newcomers, reduces availability, raises the costs of being here which ultimately creates a population of typically wealthy, conservative, unattached. This in contrast with the free wheeling, creative hippy, diverse, population of the70’s who gave Boulder that desirable open lifestyle reputation, and now has all but vanished. Gone is the pick up truck with a dog in the back, seems there are more Teslas than Subaru’s on our clogged roads now. How do you stop people swimming toward the lifeboat when it’s already at capacity? It’s not possible. I fell in love with Boulder 55 years ago like the rest of us and have to say without some of the far looking policies like the Blue Line, Boulder would look like San Francisco’s hills. R.I.P. nutty Boulder, Kinetics, mall crawl, skinny dipping in Coot lake etc, great memories the type no longer possible….We are just following human history, there is no easy answer, but still can’t just give up trying to make it better.
Death knell…
Brian, my dad moved here from NYC to get away from density in1948, and it was too populated then. This was after he nearly died as an Air Force navigator in WW2 protecting US interests of overpopulation. Handily, he evolved to become a Quaker, to advocate for the best interests for the greater good, after he shifted from a profession in the mainstream aerospace (and defense) industry to air pollution control monitoring for domestic aircraft with the FAA. So shame on you for lowering the quality of life of the Boulder he escaped NYC from, to get out of there.
Boulder doesn’t exist in a vacuum, it needs to change and grow like every other desirable community. One problem is us that us old coots are living WAY too long now and sucking up too many resources. Sorry! The demographics don’t lie. And now we are a haven for the ultra-wealthy which exacerbates every single problem we face. We definitely need more realistic and deeply thoughtful ideas of how to grow and actually improve the city. Those approaches exist but Boulder is not that innovative. The city’s idea of major innovation is cutting parking and road diets. The cart before the horse approach won’t improve anything.
The devil is in the details here, not the stats….something I also learned in my PhD, as figures/data rarely paint the complete picture. Maybe talk to your students? Because this supposed “No Growth” mantra might seem a convincing boogeyman for those who just got here with a comfortable salary. But if have lived here long enough to bear witness, you’d know this town has became far less affordable due to speculative investment not these limits, thus making it equally inhospitable to employers and job-creators alike. THIS continues to weaken our local economy, among endless exploitation of both vulnerable demos (e.g. students) and sustained strangling of local business opportunities due to the insane rents. Moreover, I’m distrustful of the Boulder Progressive (populism) sentiment, which suggests we can build our way out of these problems, reduced regulation, or increase density….all which dubiously ignores and absolves Developers for their role in how/why this town got more gentrified as well as wildly unaffordable in the first place. Because if it remains more lucrative to tear down 3 modest homes to make way for a big mansion, allow 10% of homes to sit empty to serve a wealth portfolio, or keep rental cost artificially high to protect the tax write-off for consolidated real estate holdings….Boulder will indeed remain “full”, of greedy people and Profiteers lacking any moral obligation to benefit community whatsoever.
Your concerns about investors locking up property are worth exploring!
Garrett, I hear your concerns about speculation, rising rents, and the role of profit in distorting our housing market. But the idea that limiting housing, especially multi-family housing, is the solution does not hold up. In fact, it is precisely these longstanding restrictions on housing supply, including single-family zoning that still covers the majority of Boulder, that have enabled land values to skyrocket and housing to become a speculative commodity.
The City Council is now in the process of repealing single-family-only zoning citywide, both to comply with new state law and to allow more types of homes like duplexes, triplexes, and ADUs on existing lots. This is a meaningful step toward shifting away from a scarcity-driven model that benefits only investors and longtime landowners, while pushing out everyone else.
Brian is not saying “build everything everywhere.” He is pointing out that we cannot keep pretending Boulder’s housing crisis is only about greedy developers or absentee landlords. It is also about our own zoning laws and land use decisions that have limited supply, prioritized low-density affluence, and made it increasingly difficult for working people, students, and families to live here.
Yes, we should address speculation and financialization. But we also have to remove the structural barriers that make housing scarce and unaffordable in the first place.
Interesting points, but you need to do a deep dive on how to create affordable housing that isn’t just tiny, poorly designed boxes (I won’t mention any names but look inside any of this affordable new development and ask yourself who would want to live there). Market rate infill condos or apartments around bus routes with no parking isn’t going to lure many families here. How do you imagine the demographics will improve? Also, as Lynn mentioned, jobs are a problem. The progressives seem energized at the notion of creating a Chamber of Commerce futuristic high-tech future for Boulder. Think about that: we are attracting and building a city for young, single, mobile, high tech, very well paid individuals who will only take the bus or ride bikes wherever they need to go. That doesn’t really comport with a family friendly environment anymore than the sad housing situation does. The wealth inequality will continue to grow rapidly making Boulder less and less of what made it interesting and attainable in its halycon days (and which many of us still try to find remnants of without much luck.) The future is not looking bright from what I can tell.
Roxanne: So families won’t ride bikes or take buses? Alternative transportation is for “young, single, mobile, high tech, very well paid individuals”?
Gary: please enlighten me. Show me other cities in the US with weather extremes like Boulder where a majority of families with children take the bus or ride bikes to manage all the tasks of daily living. I mean, if they do it great, but those families will have cars and they will use them. And then there’s our rapidly aging population that can’t manage it, in general.
Agree 100% Roxanne. This is an issue of (unrealistic) idealism vs reality. Unfortunately our city government has bias towards the former.
That’s the saddest part of all for me: all the miserable infill and ugly boxes aren’t going to help us keep families and contribute to a thriving community. It serves the well paid tech bros, but that’s about it. Tens of thousands of new condos and apartments, but families are fleeing this once vibrant place for families.
Infill is not going to solve anything, the housing market in Boulder is inelastic, this is born out by the data, more condos and duplexes just means more expensive housing. The only affordability will be mandated affordability, which Boulder has through the 20percent program. But the market will create none.
Canards like “the housing market in Boulder is inelastic” are great examples of topics I want to examine. There is plenty of evidence from Denver, Austin, Minneapolis, Nashville, Missoula, etc. that more housing leads to lower prices.
I’d like a clear concise definition of what “full” means.
Is it that there is truly no more vacant land available to build any kind of dwelling or even businesses on? Does it mean the streets are so clogged (aka “full”) that no one can drive anywhere any more? Does it mean that housing availability is so low that resulting supply-demand prices make it nearly impossible for anyone to live there any more, even in a small basement hovel in an old house in Goss-Grove, or out in Table Mesa?
I arrived in Boulder in 1973, and 50 years later I pine for those old days when life was somehow “normal.” It sure ain’t now.
Brian Keegan’s argument—that Boulder is not ‘full’—is simply inconclusive: he never offers readers a definition of ‘full’, so we have no basis on which to judge his considerations except for our own inclinations and interpretations. Keegan need not offer a definition on which most everyone will agree, and Keegan need not offer a definition anywhere near as precise as a potential population, but he needs to establish some reasonable baseline for argumentation. Given the subject matter of his opinion piece, crafting such a definition of ‘full’ would go a long way towards fostering constructive discussion.
I am not the one making the argument that Boulder is full so I don’t see why I bear the burden of defining it. My argument is simply that multiple lines of evidence show that Boulder was more full in the past and it is becoming less full every year.
Plenty of highly desirable and sustainable European cities have population densities that are multiples of Boulder’s (~1500 people/km2). https://en.wikipedia.org/wiki/List_of_European_Union_cities_proper_by_population_density
I suggest those so fond of European cities should go live there. I like the lower density of American cities.
The City of Boulder took the innovative and long-sighted action to conserve open space. It’s a wonderful thing. Yet now there are those who bemoan that the lack of buildable land has contributed to less homes, driving up demand and prices. Get over it. You Boulderites did the right thing to preserve the open space. Stop Monday morning quarterbacking.
Brian, thank you for this excellent article. You cut through the noise and clearly show how Boulder’s housing crisis is not an accident, but the result of decades of policy decisions that limited new housing, especially near jobs, schools, and transit.
Boulder’s zoning laws have played a central role. Single-family-only zoning still covers the majority of the city. It has prevented the construction of more diverse, affordable housing types and driven up land values, helping turn housing into a scarce and speculative commodity.
Fortunately, the City Council is now in the process of repealing single-family-only zoning citywide. This reform, prompted in part by new state law, will allow more multi-family housing options like duplexes, triplexes, and ADUs. It is a long-overdue step toward increasing housing supply, reducing displacement, and making Boulder more inclusive.
For too long, Boulder has relied on the idea that we can preserve our quality of life by limiting growth. In reality, those limitations have made it harder for the people who work here, study here, and grow up here to actually live here. You make it clear that we cannot keep using the fear of change to justify exclusion.
I especially appreciate how you challenge the “Boulder is full” myth with real data and historical context. Our land use decisions have not only made housing scarce and expensive, they have also pushed growth into other communities, creating more traffic, emissions, and environmental harm elsewhere.
This article should be required reading for anyone who believes that Boulder can live up to its progressive values. We cannot solve our housing crisis without confronting the structural barriers we created ourselves. Thank you for moving the conversation forward with clarity and urgency.
Michael, I’ll tell you about urgency, the urgency to comply with carrying capacity and population stabilization. Do you want unsustainable growth here and outlying spaces, because BOTH will happen. It’s a matter of quantifying specifically how much for which local architectural relaxations.