Williams County area

Williams County, Ohio covers 423.1 square miles: 420.7 square miles of land and 2.432 square miles of water. Its county seat is Bryan. An estimated 36,549 people lived there in 2025.

Official Census measurements · GEOID 391712026 Gazetteer · retrieved September 27, 2026
Land area420.7 mi²
Water area2.432 mi²
Population (2025)36,549
People per mi²87

County outline

Generalized outline of Williams County, Ohio
2025 Census cartographic boundary, fitted to this frame. County maps are not at a common scale. The 2026 area measurements below come from the separate Gazetteer release. Map source and limitations.

Where Williams County is located

Williams County highlighted on a map of all U.S. county equivalents. About the maps

Area breakdown

Land accounts for 99.4% of Williams County’s measured area and water for 0.6%. Its combined area converts to 1,095.8 square kilometers or approximately 270,779 acres.

Green: land · blue: water

MeasurementSquare milesSquare kilometersAcres
Land420.661,089.504269,222.4
Water2.4326.2991,556.5
Total423.0921,095.803270,778.9

How Williams County compares

By original Census land area, Williams County ranks #53 of 88 in Ohio and #2409 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.

Its land area is 0.965 times the Ohio county-equivalent median of 436 square miles. It accounts for 1% of the combined county land area in the state.

See the complete Ohio ranking · What counts as a county equivalent?

Population and density of Williams County

The Census Bureau estimates that 36,549 people lived in Williams County on July 1, 2025. That ranks #1,314 of 3,222 county equivalents nationally and #67 of 88 in Ohio. Since the April 1, 2020 estimates base of 37,106, the population has declined by 557 (−1.5%), compared with +0.9% for Ohio as a whole.

With 420.7 square miles of land, that is 87 people per square mile (34 per km²), placing Williams County #1,096 nationally for density and #65 in Ohio. The median county equivalent has 47 people per square mile; the Ohio median is 120. Put another way, there are about 7.4 acres of land per resident.

Estimated population, 2020–2025 · line scaled to this county’s own range
July 1202020212022202320242025
Estimate37,08436,79236,64236,62636,62136,549
Change—−292−150−16−5−72

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 Williams County

9 incorporated places lie at least partly in Williams County. Together they are home to 19,674 people (53.8%); the other 16,875 (46.2%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Bryan city, with 8,579 residents in the county. Among places with at least 1,000 residents in 2020, Edgerton village grew fastest since then (+0.1%).

Incorporated placePopulation 2025Since 2020Land mi²
Bryan cityCounty seat8,579−1.7%5.403
Montpelier village3,884−1.4%2.874
Edgerton village1,882+0.1%1.714
West Unity village1,735−1.2%1.539
Pioneer village1,419−1.2%2.204
Stryker village1,239−1.7%0.895
Edon village784−0.4%1.097
Blakeslee village105−1.9%0.094
Holiday City village47−2.1%2.554

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

Metropolitan area

Williams County is not part of any metropolitan or micropolitan statistical area in the Office of Management and Budget’s July 2023 delineation; 1,306 other county equivalents are also outside one. These areas are built around an urban core of at least 10,000 people plus the counties tied to it by commuting, so counties outside them are generally rural.

ZIP codes

12 ZIP Code Tabulation Areas have land in Williams County; 10 of them have most of their land inside the county, and the others mainly cover neighboring areas.

435014350243505435064351743518435214353143543435544355743570

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 Williams County

Williams County shares a land border with 6 county equivalents, including 3 in Michigan and Indiana. It has more land than 5 of them. The largest neighbor is Hillsdale County (598.2 mi²) and the smallest is Steuben County (308.8 mi²). Together with its neighbors, Williams County forms a block of 2,923.4 mi² of land, of which it holds 14.4%.

Map of Williams County and the 6 county equivalents that border it Defiance County, Ohio: 411.4 mi² landHillsdale County, Michigan: 598.2 mi² landFulton County, Ohio: 405.5 mi² landSteuben County, Indiana: 308.8 mi² landDeKalb County, Indiana: 362.8 mi² landHenry County, Ohio: 416 mi² land
Williams County (dark) and its bordering county equivalents. Select a neighbor to open its profile. Drawn from the 2025 Census cartographic boundaries in an equal-area projection. How borders are determined.
Bordering county equivalentLand mi²Size vs. WilliamsCompare
Hillsdale CountyMichigan598.21.4× largerCompare
Henry County416about the sameCompare
Defiance County411.4about the sameCompare
Fulton County405.5about the sameCompare
DeKalb CountyIndiana362.81.2× smallerCompare
Steuben CountyIndiana308.81.4× smallerCompare

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

Williams County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 2.5 times as much. Ohio’s county land could hold about 97 areas the size of Williams County.

Land area: Williams County and the closest-sized states
Williams County420.7 mi²
Rhode Island1,033.9 mi²

Another way to picture it: the same land area would fill a square about 20.5 miles (33 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 Williams County?

Williams County has more land than 813 of the other 3,221 county equivalents in the dataset.

Land area compared with the typical county equivalent
Williams County420.7 mi²
Ohio median436 mi²
National median604.5 mi²

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 Williams County at #2,478 nationally by total area, 69 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 0.6%, compared with a national county-equivalent median of 1.2% — 0.6 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 Williams County in the national ranking. They can be in different states and are not necessarily geographic neighbors.

Land rankCounty equivalentLand mi²Comparison
#2408Hood County, Texas420.7Compare
#2409Williams County, Ohio420.7This county
#2410Echols County, Georgia420.4Compare

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.

Representative coordinates

The Census internal point is 41.564959, -84.584324. It represents a location inside the geography; it is not necessarily the centroid or the address of a courthouse.

Source and precision

U.S. Census Bureau, 2026 Gazetteer Files, Counties. Original ALAND: 1,089,504,756 m²; AWATER: 6,298,925 m². Rankings use ALAND; exact ties use ascending GEOID. Tables preserve Census-published square miles to three decimals, with conversions based on those values.

Download the official county source ZIP ↗ · Methodology

Common questions

How big is Williams County?

Williams County, Ohio has 420.7 square miles (1,089.5 km²) of land and 2.432 square miles of water, for a total area of 423.1 square miles. It ranks #2409 of 3,222 U.S. county equivalents by land area.

Is Williams County the largest county in Ohio?

No. Williams County ranks #53 of 88 in Ohio by land area. The largest is Ashtabula County, with 702.4 square miles of land.

What counties border Williams County?

Williams County shares a land border with Defiance County, Hillsdale County, Michigan, Fulton County, Steuben County, Indiana, DeKalb County, Indiana, and Henry County.

What is the population of Williams County?

The Census Bureau estimates Williams County had 36,549 residents on July 1, 2025, ranking #1,314 of 3,222 county equivalents. That is 87 people per square mile of land.

What is the county seat of Williams County?

The county seat of Williams County is Bryan.

What cities and towns are in Williams County?

Williams County has 9 incorporated places. The most populous five are Bryan city, Montpelier village, Edgerton village, West Unity village, and Pioneer village; 16,875 residents live outside any incorporated place.

Is Williams County part of a metropolitan area?

No. Williams County is outside every metropolitan and micropolitan statistical area in the July 2023 OMB delineation.

How many ZIP codes are in Williams County?

12 ZIP Code Tabulation Areas have land in Williams County, and 10 of them have most of their land inside the county. Census ZIP Code Tabulation Areas approximate USPS ZIP Code areas.

How does Williams County compare with U.S. states?

It has less land than every state. Rhode Island, the smallest, has 2.5 times as much land.

How many acres of land are in Williams County?

The land measurement converts to approximately 269,222 acres. Including water, total area is approximately 270,779 acres. One square mile equals 640 acres.

Why might another source show a different area?

Check whether it reports land or total area, its Census vintage, and its rounding. Our guide explains how to reconcile county area figures.

Can this establish a property boundary?

No. Statistical measurements and generalized maps do not establish property lines. Consult the relevant local surveying or land-records authority.

Cite this county

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