Cities in Boulder County, Colorado by Population (2024)

There are 47 cities in Boulder County, Colorado.

Note: As defined by the US Census Bureau, a city's official boundaries often extend miles beyond the city itself and may even cross county lines. As such, several thousand US cities officially exist in two or more counties (and therefore appear on multiple counties' lists of cities.)

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City
Rank
State
2024 Population
2020 Census
Annual Change
Density (mi²)
Area (mi²)
Arvada1Colorado118,768124,394-1.17%3,04738.97
Westminster2Colorado112,764116,302-0.78%3,56631.62
Boulder3Colorado102,858108,112-1.26%3,82526.89
Longmont4Colorado98,19399,181-0.25%3,38229.04
Broomfield5Colorado77,75874,4841.06%2,35932.97
Northglenn6Colorado38,17438,0380.09%5,1877.36
Erie7Colorado35,80330,4053.92%1,72620.74
Wheat Ridge8Colorado31,37732,381-0.79%3,3589.34
Lafayette9Colorado30,97630,4220.45%3,3569.23
Golden10Colorado20,53320,3870.18%2,1319.63
Firestone11Colorado19,96316,6654.31%1,43613.90
Louisville12Colorado19,94721,173-1.51%2,5027.97
Johnstown13Colorado19,90717,3653.3%1,29015.44
Frederick14Colorado19,59214,7246.62%1,28815.21
Berthoud15Colorado14,81510,6057.65%1,14013
Superior16Colorado13,47913,1050.7%3,4273.93
Fairmount17Colorado11,2479,5493.93%1,8506.08
Gunbarrel18Colorado9,92610,494-0.91%1,5896.25
Mead19Colorado7,6884,80010.37%51115.04
Dacono20Colorado6,6286,3481.07%7159.28
Niwot21Colorado4,0974,0850.07%1,0254
Platteville22Colorado2,9222,958-0.31%9363.12
Coal Creek23Colorado2,2572,605-3.71%2409.39
Lyons24Colorado2,0832,209-1.47%1,5431.35
Nederland25Colorado1,5351,4651.19%1,0371.48
Lazy Acres26Colorado9571,071-2.84%1815.29
Paragon Estates27Colorado9277853.92%5531.68
Allenspark28Colorado7184647.16%6011.94
Altona29Colorado5834794.67%3461.69
Sugarloaf30Colorado5732626.7%2632.18
Crisman31Colorado4665127.67%3201.46
St. Ann Highlands32Colorado418486-3.91%3011.39
Eldora33Colorado357352-3.25%864.16
Tall Timber34Colorado316295-12.95%5510.57
Pine Brook Hill35Colorado266776-32.32%883.03
Eldorado Springs36Colorado262325-4.03%1012.58
Jamestown37Colorado242254-1.22%4220.57
Sunshine38Colorado2161450.94%1251.73
Gold Hill39Colorado203195-10.18%982.08
Mountain Meadows40Colorado1841741.66%1071.72
Bark Ranch41Colorado1511077.86%1750.86
Seven Hills42Colorado1391272.21%2840.49
Ward43Colorado126130-0.79%2350.54
Bonanza Mountain Estates44Colorado103174-12.71%6130.17
Valmont45Colorado6498-11.11%2480.26
Glendale46Colorado32109-36%251.25
Hidden Lake47Colorado28300%460.61
showing: 47 rows

Note: City markers shown outside the county boundary mean that a part of the city extends into this county, but is primarily located in an adjacent county.

What is the largest city in Boulder County, Colorado?

Arvada is the largest city in Boulder County.

What is the smallest city in Boulder County, Colorado?

Hidden Lake is the smallest city in Boulder County.

How many cities are in Boulder County?

There are 47 cities in Boulder County, Colorado.

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