County outline
Where Benton County is located
Area breakdown
Land accounts for 99.6% of Benton County’s measured area and water for 0.4%. Its combined area converts to 1,756.4 square kilometers or approximately 434,025 acres.
Green: land · blue: water
| Measurement | Square miles | Square kilometers | Acres |
|---|---|---|---|
| Land | 675.208 | 1,748.781 | 432,133.1 |
| Water | 2.956 | 7.656 | 1,891.8 |
| Total | 678.164 | 1,756.437 | 434,025 |
How Benton County compares
By original Census land area, Benton County ranks #33 of 36 in Oregon and #1393 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.
Its land area is 0.37 times the Oregon county-equivalent median of 1,826.2 square miles. It accounts for 0.7% of the combined county land area in the state.
See the complete Oregon ranking · What counts as a county equivalent?
Population and density of Benton County
The Census Bureau estimates that 97,728 people lived in Benton County on July 1, 2025. That ranks #645 of 3,222 county equivalents nationally and #11 of 36 in Oregon. Since the April 1, 2020 estimates base of 95,178, the population has grown by 2,550 (+2.7%), compared with +0.9% for Oregon as a whole.
With 675.2 square miles of land, that is 145 people per square mile (56 per km²), placing Benton County #797 nationally for density and #6 in Oregon. The median county equivalent has 47 people per square mile; the Oregon median is 25. Put another way, there are about 4.4 acres of land per resident.
| July 1 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 |
|---|---|---|---|---|---|---|
| Estimate | 93,602 | 93,012 | 97,281 | 97,964 | 97,590 | 97,728 |
| Change | — | −590 | +4,269 | +683 | −374 | +138 |
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 Benton County
5 incorporated places lie at least partly in Benton County. Together they are home to 78,098 people (79.9%); the other 19,630 (20.1%) live outside any incorporated place, in unincorporated communities and rural areas.
The largest is Corvallis city, with 61,499 residents in the county. By land, Albany city is the largest at 17.9 mi² across all its counties. Among places with at least 1,000 residents in 2020, Philomath city grew fastest since then (+6.5%).
| Incorporated place | Population 2025 | Since 2020 | Land mi² |
|---|---|---|---|
| Corvallis cityCounty seat | 61,499 | +2.6% | 14.6 |
| Albany cityAlso in 1 other county | 9,225 | +0.9% | 17.9 |
| Philomath city | 5,699 | +6.5% | 2.07 |
| Adair Village city | 1,010 | +2.4% | 0.535 |
| Monroe city | 665 | +2.9% | 0.515 |
Population: U.S. Census Bureau Vintage 2025 subcounty estimates, counting only the part of each place inside Benton County. Land: 2026 Census Gazetteer, for the whole place even where it extends into other counties. How communities are listed.
Metropolitan area
Benton County is a central county of the Corvallis, OR Metropolitan Statistical Area. Benton County is the area’s only county equivalent, so the metro area has the same 675.2 square miles of land. By combined land it ranks #328 of 393 metropolitan areas, and #373 by population. It belongs to the Portland-Vancouver-Salem, OR-WA Combined Statistical Area.
ZIP codes
10 ZIP Code Tabulation Areas have land in Benton County; 6 of them have most of their land inside the county, and the others mainly cover neighboring areas.
97321973249732697330973319733397361973709744897456
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 Benton County
Benton County shares a land border with 4 county equivalents. Each of them has more land than Benton County. The largest neighbor is Lane County (4,554.1 mi²) and the smallest is Polk County (740.9 mi²). Together with its neighbors, Benton County forms a block of 9,240.7 mi² of land, of which it holds 7.3%.
| Bordering county equivalent | Land mi² | Size vs. Benton | Compare |
|---|---|---|---|
| Lane County | 4,554.1 | 6.7× larger | Compare |
| Linn County | 2,289.5 | 3.4× larger | Compare |
| Lincoln County | 981 | 1.5× larger | Compare |
| Polk County | 740.9 | 1.1× larger | Compare |
How big is Benton County compared with U.S. states?
Benton County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 1.5 times as much. Oregon’s county land could hold about 142 areas the size of Benton County.
Another way to picture it: the same land area would fill a square about 26 miles (41.8 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 Benton County?
Benton County has more land than 1,829 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 Benton County at #1,499 nationally by total area, 106 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 0.4%, compared with a national county-equivalent median of 1.2% — 0.7 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 Benton County in the national ranking. They can be in different states and are not necessarily geographic neighbors.
| Land rank | County equivalent | Land mi² | Comparison |
|---|---|---|---|
| #1392 | Greene County, Missouri | 675.3 | Compare |
| #1393 | Benton County, Oregon | 675.2 | This county |
| #1394 | Platte County, Nebraska | 675.2 | Compare |
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 44.513027, -123.408779. 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: 1,748,781,828 m²; AWATER: 7,655,315 m². Rankings use ALAND; exact ties use ascending GEOID. Tables preserve Census-published square miles to three decimals, with conversions based on those values.
Common questions
How big is Benton County?
Benton County, Oregon has 675.2 square miles (1,748.8 km²) of land and 2.956 square miles of water, for a total area of 678.2 square miles. It ranks #1393 of 3,222 U.S. county equivalents by land area.
Is Benton County the largest county in Oregon?
No. Benton County ranks #33 of 36 in Oregon by land area. The largest is Harney County, with 10,134.5 square miles of land.
What counties border Benton County?
Benton County shares a land border with Linn County, Lincoln County, Lane County, and Polk County.
What is the population of Benton County?
The Census Bureau estimates Benton County had 97,728 residents on July 1, 2025, ranking #645 of 3,222 county equivalents. That is 145 people per square mile of land.
What is the county seat of Benton County?
The county seat of Benton County is Corvallis.
What cities and towns are in Benton County?
Benton County has 5 incorporated places. The most populous are Corvallis city, Albany city, Philomath city, Adair Village city, and Monroe city; 19,630 residents live outside any incorporated place.
Is Benton County part of a metropolitan area?
Yes. It is a central county of the Corvallis, OR Metropolitan Statistical Area.
How many ZIP codes are in Benton County?
10 ZIP Code Tabulation Areas have land in Benton County, and 6 of them have most of their land inside the county. Census ZIP Code Tabulation Areas approximate USPS ZIP Code areas.
How does Benton County compare with U.S. states?
It has less land than every state. Rhode Island, the smallest, has 1.5 times as much land.
How many acres of land are in Benton County?
The land measurement converts to approximately 432,133 acres. Including water, total area is approximately 434,025 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.