The Line Boulder Drew on a Map

In nineteen fifty-nine, the voters of Boulder decided to draw a line. It ran along an elevation contour on the western edge of town, roughly five thousand seven hundred feet above sea level. Above that line, the city would not extend its water and sewer service. No service, no development. The mountain slopes above Boulder would stay as they were.

It was called the Blue Line. At the time, no other American city had done anything quite like it. The idea of using infrastructure policy as a growth-management tool, of deliberately constraining the city's own expansion, was almost unprecedented in American municipal politics. This was not a scenic-highway designation or a conservation easement; it was a decision to limit what the city itself would build.

In nineteen sixty-seven Boulder approved an open space ordinance, beginning to purchase the ring of undeveloped land around the city that today defines its character. In nineteen seventy-one the city adopted one of the first urban growth boundaries in the country.

The landscape that resulted from these decisions is genuinely extraordinary. The Flatirons rise directly from the edge of the built environment. You can walk from a coffee shop to wilderness in fifteen minutes. The mountain backdrop that makes Boulder's visual identity is real and accessible.

The cost of these decisions is also measurable. Boulder is one of the least affordable cities in Colorado, and among the least affordable in the Rocky Mountain West. The restrictions that preserved the landscape also constrained the housing supply. The people who give Boulder its counterculture reputation, the artists, the graduate students, the eccentrics, often cannot afford to live here anymore. Conservation and affordability are in direct tension, and Boulder's history is a clear example of what happens when conservation wins.