Lewis County area

Population and density of Lewis County

The Census Bureau estimates that 9,879 people lived in Lewis County on July 1, 2025. That ranks #2,489 of 3,222 county equivalents nationally and #86 of 115 in Missouri. Since the April 1, 2020 estimates base of 10,038, the population has declined by 159 (−1.6%), compared with +1.9% for Missouri as a whole.

With 505 square miles of land, that is 20 people per square mile (7.6 per km²), placing Lewis County #2,341 nationally for density and #82 in Missouri. The median county equivalent has 47 people per square mile; the Missouri median is 31. Put another way, there are about 33 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 Lewis County

6 incorporated places lie at least partly in Lewis County. Together they are home to 5,234 people (53%); the other 4,645 (47%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Canton city, with 2,763 residents in the county. The county seat, Monticello village, has 105 residents.

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

Metropolitan area

Lewis County is an outlying county of the Quincy, IL-MO Micropolitan Statistical Area. Its 2 county equivalents have 74,146 residents on 1,360.2 square miles of land; Lewis County accounts for 37.1% of the land and 13.3% of the residents. By combined land it ranks #126 of 542 micropolitan areas, and #90 by population. It belongs to the Quincy-Hannibal, IL-MO Combined Statistical Area.

ZIP codes

12 ZIP Code Tabulation Areas have land in Lewis County; 8 of them have most of their land inside the county, and the others mainly cover neighboring areas.

634356343863440634466344763448634526345463457634716347363474

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 Lewis County

Lewis County shares a land border with 6 county equivalents, including 2 in Illinois. It has more land than 4 of them. The largest neighbor is Adams County (855.2 mi²) and the smallest is Marion County (436.9 mi²). Together with its neighbors, Lewis County forms a block of 4,100.3 mi² of land, of which it holds 12.3%.

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

Lewis 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 times as much. Missouri’s county land could hold about 136 areas the size of Lewis County.

Another way to picture it: the same land area would fill a square about 22.5 miles (36.2 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 Lewis County?

Lewis County has more land than 1,166 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 Lewis County at #2,135 nationally by total area, 79 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 1.1%, compared with a national county-equivalent median of 1.2%. The two percentages are within 0.1 percentage points of each other. 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 Lewis 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.