Oldham County area

Population and density of Oldham County

The Census Bureau estimates that 70,986 people lived in Oldham County on July 1, 2025. That ranks #789 of 3,222 county equivalents nationally and #11 of 120 in Kentucky. Since the April 1, 2020 estimates base of 67,614, the population has grown by 3,372 (+5%), compared with +2.2% for Kentucky as a whole.

With 187.3 square miles of land, that is 379 people per square mile (146 per km²), placing Oldham County #429 nationally for density and #6 in Kentucky. The median county equivalent has 47 people per square mile; the Kentucky median is 59. Put another way, there are about 1.7 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 Oldham County

7 incorporated places lie at least partly in Oldham County. Together they are home to 22,001 people (31%); the other 48,985 (69%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is La Grange city, with 10,669 residents in the county. Among places with at least 1,000 residents in 2020, La Grange city grew fastest since then (+5.9%).

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

Metropolitan area

Oldham County is a central county of the Louisville/Jefferson County, KY-IN Metropolitan Statistical Area. Its 12 county equivalents have 1,402,509 residents on 3,960.8 square miles of land; Oldham County accounts for 4.7% of the land and 5.1% of the residents. By combined land it ranks #74 of 393 metropolitan areas, and #44 by population. It belongs to the Louisville/Jefferson County--Elizabethtown, KY-IN Combined Statistical Area.

ZIP codes

11 ZIP Code Tabulation Areas have land in Oldham County; 7 of them have most of their land inside the county, and the others mainly cover neighboring areas.

4001040014400264003140055400564005940068400774024140245

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 Oldham County

Oldham County shares a land border with 5 county equivalents, including 1 in Indiana. It has more land than 1 of them. The largest neighbor is Jefferson County (380.8 mi²) and the smallest is Trimble County (147.8 mi²). Together with its neighbors, Oldham County forms a block of 1,754.4 mi² of land, of which it holds 10.7%.

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

Oldham County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 5.5 times as much. Kentucky’s county land could hold about 211 areas the size of Oldham County.

Another way to picture it: the same land area would fill a square about 13.7 miles (22 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 Oldham County?

Oldham County has more land than 205 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 Oldham County at #3,031 nationally by total area, 14 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 4.6%, compared with a national county-equivalent median of 1.2% — 3.4 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 Oldham 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.