Larimer County area

Population and density of Larimer County

The Census Bureau estimates that 377,292 people lived in Larimer County on July 1, 2025. That ranks #207 of 3,222 county equivalents nationally and #8 of 64 in Colorado. Since the April 1, 2020 estimates base of 359,069, the population has grown by 18,223 (+5.1%), compared with +4.1% for Colorado as a whole.

With 2,595.7 square miles of land, that is 145 people per square mile (56 per km²), placing Larimer County #794 nationally for density and #9 in Colorado. The median county equivalent has 47 people per square mile; the Colorado median is 11. Put another way, there are about 4.4 acres of land per resident.

U.S. Census Bureau, Vintage 2025 population estimates. Estimates are revised each year and are not decennial census counts. Density divides the whole population by the whole county’s land area, so it describes an average, not how settlement is distributed within the county. Population sources and methods.

Cities and towns in Larimer County

8 incorporated places lie at least partly in Larimer County. Together they are home to 311,800 people (82.6%); the other 65,492 (17.4%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Fort Collins city, with 171,500 residents in the county. Among places with at least 1,000 residents in 2020, Timnath town grew fastest since then (+78.5%).

Population: U.S. Census Bureau Vintage 2025 subcounty estimates, counting only the part of each place inside Larimer County. Land: 2026 Census Gazetteer, for the whole place even where it extends into other counties. How communities are listed.

Metropolitan area

Larimer County is a central county of the Fort Collins-Loveland, CO Metropolitan Statistical Area. Larimer County is the area’s only county equivalent, so the metro area has the same 2,595.7 square miles of land. By combined land it ranks #126 of 393 metropolitan areas, and #151 by population.

ZIP codes

24 ZIP Code Tabulation Areas have land in Larimer County; 18 of them have most of their land inside the county, and the others mainly cover neighboring areas.

805038050480512805138051580517805218052480525805268052880532805348053580536805378053880540805458054780549805508061282063

ZIP Code Tabulation Areas are the Census Bureau’s approximations of USPS ZIP Code service areas, from the 2020 Census relationship files. Lighter codes have less than half of their land in this county. Post-office-box and single-address ZIP Codes have no tabulation area.

Counties bordering Larimer County

Larimer County shares a land border with 6 county equivalents, including 2 in Wyoming. It has more land than 3 of them. The largest neighbor is Albany County (4,274.2 mi²) and the smallest is Boulder County (726.4 mi²). Together with its neighbors, Larimer County forms a block of 17,727.5 mi² of land, of which it holds 14.6%.

How big is Larimer County compared with U.S. states?

Larimer County has more land than 2 of the 50 states. It is about 1.3 times the land area of Delaware (1,948.6 mi²), while Connecticut, the next larger state, has 1.9 times as much land (4,842.5 mi²). Colorado’s county land could hold about 40 areas the size of Larimer County.

Another way to picture it: the same land area would fill a square about 50.9 miles (82 km) on each side. Real county shapes are rarely square, so this is a scale reference rather than a width or driving distance.

State figures are the sums of each state’s county-equivalent land measurements in the same Census release, so states and counties are compared on the same basis. Published state totals can differ slightly because of rounding. Compare all states · Counties bigger than entire states.

What stands out about Larimer County?

Larimer County has more land than 3,017 of the other 3,221 county equivalents in the dataset.

A median is the middle county-equivalent measurement, not the average of the largest and smallest. All three bars use the same linear scale. Very small areas may appear as a thin sliver; the labels retain their values.

Does including water change its rank?

Using land plus water places Larimer County at #216 nationally by total area, 11 places farther from the top than its land rank. Other county equivalents gain more area when their water measurements are included.

Its water share is 1.5%, compared with a national county-equivalent median of 1.2% — 0.3 percentage points higher. This describes the statistical geography’s land/water mix, not flood exposure or developable land.

Closest positions in the national land ranking

These entries sit immediately beside Larimer County in the national ranking. They can be in different states and are not necessarily geographic neighbors.

Calculated from the same Census release as the area table. Total-area order uses original ALAND + AWATER; water shares and chart labels use published square miles. Calculation details.