Butler County area

Population and density of Butler County

The Census Bureau estimates that 400,128 people lived in Butler County on July 1, 2025. That ranks #194 of 3,222 county equivalents nationally and #7 of 88 in Ohio. Since the April 1, 2020 estimates base of 390,345, the population has grown by 9,783 (+2.5%), compared with +0.9% for Ohio as a whole.

With 466.5 square miles of land, that is 858 people per square mile (331 per km²), placing Butler County #216 nationally for density and #8 in Ohio. The median county equivalent has 47 people per square mile; the Ohio median is 120. Put another way, there are about 0.746 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 Butler County

12 incorporated places lie at least partly in Butler County. Together they are home to 216,290 people (54.1%); the other 183,838 (45.9%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Hamilton city, with 64,644 residents in the county. By land, Middletown city is the largest at 26.3 mi² across all its counties. Among places with at least 1,000 residents in 2020, Trenton city grew fastest since then (+9.5%).

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

Metropolitan area

Butler County is a central county of the Cincinnati, OH-KY-IN Metropolitan Statistical Area. Its 15 county equivalents have 2,312,858 residents on 4,385.2 square miles of land; Butler County accounts for 10.6% of the land and 17.3% of the residents. By combined land it ranks #60 of 393 metropolitan areas, and #30 by population. It belongs to the Cincinnati-Wilmington, OH-KY-IN Combined Statistical Area.

ZIP codes

18 ZIP Code Tabulation Areas have land in Butler County; 14 of them have most of their land inside the county, and the others mainly cover neighboring areas.

450034501145013450144501545042450444505045053450554505645062450644506745069452414524645327

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 Butler County

Butler County shares a land border with 6 county equivalents, including 2 in Indiana. It has more land than every one of them. The largest neighbor is Montgomery County (461.4 mi²) and the smallest is Union County (161.2 mi²). Together with its neighbors, Butler County forms a block of 2,704.6 mi² of land, of which it holds 17.2%.

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

Butler County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 2.2 times as much. Ohio’s county land could hold about 88 areas the size of Butler County.

Another way to picture it: the same land area would fill a square about 21.6 miles (34.8 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 Butler County?

Butler County has more land than 1,016 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 Butler County at #2,282 nationally by total area, 76 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 0.8%, compared with a national county-equivalent median of 1.2% — 0.4 percentage points lower. 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 Butler 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.