Collin County area

Population and density of Collin County

The Census Bureau estimates that 1,297,179 people lived in Collin County on July 1, 2025. That ranks #33 of 3,222 county equivalents nationally and #6 of 254 in Texas. Since the April 1, 2020 estimates base of 1,066,201, the population has grown by 230,978 (+21.7%), compared with +8.8% for Texas as a whole.

With 841.6 square miles of land, that is 1,541 people per square mile (595 per km²), placing Collin County #113 nationally for density and #5 in Texas. The median county equivalent has 47 people per square mile; the Texas median is 22. Put another way, there are about 0.415 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 Collin County

32 incorporated places lie at least partly in Collin County. Together they are home to 1,239,213 people (95.5%); the other 57,966 (4.5%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Plano city, with 287,323 residents in the county (the city extends into 1 other county). The county seat, McKinney city, has 236,001 residents. By land, Dallas city is the largest at 339.6 mi² across all its counties. Among places with at least 1,000 residents in 2020, Josephine city grew fastest since then (+372.7%).

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

Metropolitan area

Collin County is a central county of the Dallas-Fort Worth-Arlington, TX Metropolitan Statistical Area, in the Dallas-Plano-Irving, TX metropolitan division. Its 11 county equivalents have 8,477,157 residents on 8,675.6 square miles of land; Collin County accounts for 9.7% of the land and 15.3% of the residents. By combined land it ranks #11 of 393 metropolitan areas, and #4 by population. It belongs to the Dallas-Fort Worth, TX-OK Combined Statistical Area.

ZIP codes

40 ZIP Code Tabulation Areas have land in Collin County; 29 of them have most of their land inside the county, and the others mainly cover neighboring areas.

75002750077500975013750237502475025750337503475035750447504875069750707507175072750747507575078750807508275087750937509475098751647516675173751897524875252752877540775409754247544275452754547549175495

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 Collin County

Collin County shares a land border with 6 county equivalents. It has more land than 2 of them. The largest neighbor is Grayson County (932.8 mi²) and the smallest is Rockwall County (127.2 mi²). Together with its neighbors, Collin County forms a block of 5,371.3 mi² of land, of which it holds 15.7%.

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

Collin County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 1.2 times as much. Texas’s county land could hold about 310 areas the size of Collin County.

Another way to picture it: the same land area would fill a square about 29 miles (46.7 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 Collin County?

Collin County has more land than 2,232 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 Collin County at #1,015 nationally by total area, 25 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 5%, compared with a national county-equivalent median of 1.2% — 3.8 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 Collin 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.