County outline
Where Olmsted County is located
Area breakdown
Land accounts for 99.8% of Olmsted County’s measured area and water for 0.2%. Its combined area converts to 1,695.8 square kilometers or approximately 419,043 acres.
Green: land · blue: water
| Measurement | Square miles | Square kilometers | Acres |
|---|---|---|---|
| Land | 653.509 | 1,692.581 | 418,245.8 |
| Water | 1.245 | 3.225 | 796.8 |
| Total | 654.754 | 1,695.805 | 419,042.6 |
How Olmsted County compares
By original Census land area, Olmsted County ranks #46 of 87 in Minnesota and #1440 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.
Its land area is 0.969 times the Minnesota county-equivalent median of 674.6 square miles. It accounts for 0.8% of the combined county land area in the state.
See the complete Minnesota ranking · What counts as a county equivalent?
Population and density of Olmsted County
The Census Bureau estimates that 166,731 people lived in Olmsted County on July 1, 2025. That ranks #425 of 3,222 county equivalents nationally and #7 of 87 in Minnesota. Since the April 1, 2020 estimates base of 162,855, the population has grown by 3,876 (+2.4%), compared with +2.2% for Minnesota as a whole.
With 653.5 square miles of land, that is 255 people per square mile (99 per km²), placing Olmsted County #564 nationally for density and #8 in Minnesota. The median county equivalent has 47 people per square mile; the Minnesota median is 27. Put another way, there are about 2.5 acres of land per resident.
| July 1 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 |
|---|---|---|---|---|---|---|
| Estimate | 163,055 | 163,717 | 163,908 | 164,841 | 165,777 | 166,731 |
| Change | — | +662 | +191 | +933 | +936 | +954 |
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 Olmsted County
Olmsted County is divided into 26 municipalities and townships. In Minnesota, county subdivisions are local governments, and together they cover all of the county’s land and residents.
The most populous is Rochester city, with 124,292 residents (74.5% of the county), and it is also the largest by land at 57.9 mi². Among those with at least 1,000 residents in 2020, Oronoco city grew fastest since then (+12.5%).
| County subdivision | Population 2025 | Since 2020 | Land mi² | Share of county land |
|---|---|---|---|---|
| Rochester cityCounty seat | 124,292 | +2.4% | 57.9 | 8.9% |
| Stewartville city | 6,850 | +2.4% | 3.401 | 0.5% |
| Byron city | 6,740 | +6.7% | 3.181 | 0.5% |
| Marion township | 4,111 | +2.1% | 29.1 | 4.4% |
| Cascade township | 2,810 | −1.1% | 11.2 | 1.7% |
| Oronoco township | 2,491 | +1.8% | 31.3 | 4.8% |
| Rochester townshipCounty seat | 2,280 | +9.9% | 17.6 | 2.7% |
| Oronoco city | 2,043 | +12.5% | 2.932 | 0.4% |
| Eyota city | 2,013 | +0.6% | 1.688 | 0.3% |
| Haverhill township | 1,473 | −1.6% | 31.7 | 4.9% |
| New Haven township | 1,259 | +1% | 33.5 | 5.1% |
| Kalmar township | 1,157 | +3.4% | 31.9 | 4.9% |
| Chatfield city | 1,152 | −1.4% | 0.914 | 0.1% |
| Salem township | 1,058 | −3.1% | 35.8 | 5.5% |
| High Forest township | 940 | −3.5% | 39.5 | 6% |
Show the other 11 subdivisions
| Name | Population 2025 | Since 2020 | Land mi² |
|---|---|---|---|
| Pine Island city | 902 | +1% | 2.942 |
| Dover city | 761 | −3.1% | 1.004 |
| Pleasant Grove township | 723 | −4.1% | 35.8 |
| Rock Dell township | 681 | −0.3% | 35.9 |
| Orion township | 529 | −2.6% | 35.6 |
| Viola township | 527 | −4.2% | 35.7 |
| Eyota township | 496 | +2.1% | 34.1 |
| Dover township | 385 | −1.5% | 34.9 |
| Farmington township | 379 | −5.3% | 35.5 |
| Elmira township | 347 | +2.1% | 34.9 |
| Quincy township | 332 | +1.8% | 35.8 |
Population: U.S. Census Bureau Vintage 2025 subcounty estimates, counting only the part of each subdivision inside Olmsted County. Land: 2026 Census Gazetteer. How communities are listed.
Metropolitan area
Olmsted County is a central county of the Rochester, MN Metropolitan Statistical Area. Its 4 county equivalents have 231,184 residents on 2,477.2 square miles of land; Olmsted County accounts for 26.4% of the land and 72.1% of the residents. By combined land it ranks #132 of 393 metropolitan areas, and #210 by population. It belongs to the Rochester-Austin-Winona, MN Combined Statistical Area.
| County equivalent | Population 2025 | Land mi² |
|---|---|---|
| Olmsted County | 166,731 | 653.5 |
| Fillmore County | 21,540 | 861.3 |
| Wabasha County | 21,537 | 523 |
| Dodge County | 21,376 | 439.4 |
ZIP codes
21 ZIP Code Tabulation Areas have land in Olmsted County; 12 of them have most of their land inside the county, and the others mainly cover neighboring areas.
559015590255903559045590555906559205592355929559325593455940559445595555956559605596355964559725597655991
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 Olmsted County
Olmsted County shares a land border with 6 county equivalents. It has more land than 3 of them. The largest neighbor is Fillmore County (861.3 mi²) and the smallest is Dodge County (439.4 mi²). Together with its neighbors, Olmsted County forms a block of 4,571.4 mi² of land, of which it holds 14.3%.
| Bordering county equivalent | Land mi² | Size vs. Olmsted | Compare |
|---|---|---|---|
| Fillmore County | 861.3 | 1.3× larger | Compare |
| Goodhue County | 756.7 | 1.2× larger | Compare |
| Mower County | 711.3 | 1.1× larger | Compare |
| Winona County | 626.2 | about the same | Compare |
| Wabasha County | 523 | 1.2× smaller | Compare |
| Dodge County | 439.4 | 1.5× smaller | Compare |
How big is Olmsted County compared with U.S. states?
Olmsted County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 1.6 times as much. Minnesota’s county land could hold about 122 areas the size of Olmsted County.
Another way to picture it: the same land area would fill a square about 25.6 miles (41.1 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 Olmsted County?
Olmsted County has more land than 1,782 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 Olmsted County at #1,561 nationally by total area, 121 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 0.2%, compared with a national county-equivalent median of 1.2% — 1 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 Olmsted County in the national ranking. They can be in different states and are not necessarily geographic neighbors.
| Land rank | County equivalent | Land mi² | Comparison |
|---|---|---|---|
| #1439 | Madison County, New York | 654.9 | Compare |
| #1440 | Olmsted County, Minnesota | 653.5 | This county |
| #1441 | Armstrong County, Pennsylvania | 653.3 | 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 43.999628, -92.410411. 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: 1,692,581,227 m²; AWATER: 3,225,617 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 Olmsted County?
Olmsted County, Minnesota has 653.5 square miles (1,692.6 km²) of land and 1.245 square miles of water, for a total area of 654.8 square miles. It ranks #1440 of 3,222 U.S. county equivalents by land area.
Is Olmsted County the largest county in Minnesota?
No. Olmsted County ranks #46 of 87 in Minnesota by land area. The largest is St. Louis County, with 6,248.1 square miles of land.
What counties border Olmsted County?
Olmsted County shares a land border with Wabasha County, Dodge County, Fillmore County, Winona County, Mower County, and Goodhue County.
What is the population of Olmsted County?
The Census Bureau estimates Olmsted County had 166,731 residents on July 1, 2025, ranking #425 of 3,222 county equivalents. That is 255 people per square mile of land.
What is the county seat of Olmsted County?
The county seat of Olmsted County is Rochester.
What cities and towns are in Olmsted County?
Olmsted County has 26 county subdivisions (cities, towns and townships). The most populous five are Rochester city, Stewartville city, Byron city, Marion township, and Cascade township.
Is Olmsted County part of a metropolitan area?
Yes. It is a central county of the Rochester, MN Metropolitan Statistical Area, which has 4 county equivalents and 231,184 residents.
How many ZIP codes are in Olmsted County?
21 ZIP Code Tabulation Areas have land in Olmsted County, and 12 of them have most of their land inside the county. Census ZIP Code Tabulation Areas approximate USPS ZIP Code areas.
How does Olmsted County compare with U.S. states?
It has less land than every state. Rhode Island, the smallest, has 1.6 times as much land.
How many acres of land are in Olmsted County?
The land measurement converts to approximately 418,246 acres. Including water, total area is approximately 419,043 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.