Arapahoe County, Colorado

County seat: Littleton · Population 673,820 (2025) · 798 sq mi

Arapahoe County is the 3rd most populous of Colorado's 64 counties, with 673,820 people (2025 estimate). Its county seat is Littleton. It is part of the Region 3: Denver Metropolitan Area region, one of the 14 Planning and Management Regions of Colorado. The map shows its 13 cities and towns and the 7 neighboring counties.

Map of Arapahoe County, Colorado with cities, towns and the county boundary
Arapahoe County, Colorado with its cities and towns, unincorporated communities (CDPs) and neighboring counties. Boundaries: U.S. Census Bureau, 2025. Free to use with attribution (CC BY 4.0).
Download PDF (Letter) 130 KBPNG image 82 KBColorado county map

Arapahoe County facts

County seat
Littleton
Population (2025 estimate)
673,820 +2.9% since 2020
Land area
798 sq mi 48th largest of 64
Water area
8 sq mi
Population density
845 per sq mi
Established
1861
Named after
Arapahoe County former county of Kansas Territory
Largest city
Aurora 344,658 in the county
Median household income
$101,087
Cities and towns
13 plus 13 CDPs
ZIP codes
33
Time zone
Mountain
FIPS code
08005

Cities and towns in Arapahoe County

Arapahoe County has 13 incorporated cities, towns and villages. Populations count the people living inside Arapahoe County; cities that cross a county line also list the other counties.

NameTypePopulation 2025Also in
AuroraCity344,658Adams and Douglas counties
CentennialCity108,658
Littleton (county seat)City43,419Douglas and Jefferson counties
EnglewoodCity35,305
Greenwood VillageCity15,323
Cherry Hills VillageCity6,389
SheridanCity5,972
GlendaleCity4,475
Deer TrailTown1,755
Columbine ValleyTown1,684
FoxfieldTown746
Bow MarTown576Jefferson County
BennettTown447Adams County

Unincorporated communities (CDPs)

Census-designated places are communities without their own city government; the county provides their services.

CommunityPopulationAlso in
Four Square Mile23,024
Cherry Creek10,721
Dove Valley4,806
Inverness2,934
Holly Hills2,572
Columbine2,034Jefferson County
Byers1,726
Strasburg1,284Adams County
Aetna Estates1,010
Watkins784Adams County
Comanche Creek283
Brick Center105
Peoria75

ZIP codes in Arapahoe County

33 ZIP codes reach into Arapahoe County. ZIP codes ignore county lines, so some also cover a neighboring county.

Population of Arapahoe County, 2020–2025

Arapahoe County grew by 18,735 people (+2.9%) between April 2020 and July 2025: 15,242 more births than deaths and a net gain of 2,983 people from migration.

Year (July 1)Population
2020655,269
2021657,020
2022659,472
2023665,778
2024675,760
2025673,820

Neighboring counties

Printable Arapahoe County map

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Sources

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