Simpson County area

Population and density of Simpson County

The Census Bureau estimates that 20,788 people lived in Simpson County on July 1, 2025. That ranks #1,846 of 3,222 county equivalents nationally and #56 of 120 in Kentucky. Since the April 1, 2020 estimates base of 19,595, the population has grown by 1,193 (+6.1%), compared with +2.2% for Kentucky as a whole.

With 234.2 square miles of land, that is 89 people per square mile (34 per km²), placing Simpson County #1,082 nationally for density and #38 in Kentucky. The median county equivalent has 47 people per square mile; the Kentucky median is 59. Put another way, there are about 7.2 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 Simpson County

1 incorporated place lies at least partly in Simpson County. Together they are home to 10,759 people (51.8%); the other 10,029 (48.2%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Franklin city, with 10,759 residents in the county.

Metropolitan area

Simpson County is a central county of the Franklin, KY Micropolitan Statistical Area. Simpson County is the area’s only county equivalent, so the micro area has the same 234.2 square miles of land. By combined land it ranks #531 of 542 micropolitan areas, and #508 by population. It belongs to the Bowling Green-Glasgow-Franklin, KY Combined Statistical Area.

ZIP codes

5 ZIP Code Tabulation Areas have land in Simpson County; 1 of them have most of their land inside the county, and the others mainly cover neighboring areas.

4210442134421704220242206

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 Simpson County

Simpson County shares a land border with 5 county equivalents, including 2 in Tennessee. Each of them has more land than Simpson County. The largest neighbor is Logan County (552.2 mi²) and the smallest is Allen County (343.7 mi²). Together with its neighbors, Simpson County forms a block of 2,677.7 mi² of land, of which it holds 8.7%.

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

Simpson County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 4.4 times as much. Kentucky’s county land could hold about 169 areas the size of Simpson County.

Another way to picture it: the same land area would fill a square about 15.3 miles (24.6 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 Simpson County?

Simpson County has more land than 282 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 Simpson County at #2,970 nationally by total area, 30 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 1%, compared with a national county-equivalent median of 1.2% — 0.2 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 Simpson 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.