Waldo County area

Population and density of Waldo County

The Census Bureau estimates that 40,693 people lived in Waldo County on July 1, 2025. That ranks #1,197 of 3,222 county equivalents nationally and #11 of 16 in Maine. Since the April 1, 2020 estimates base of 39,606, the population has grown by 1,087 (+2.7%), compared with +3.8% for Maine as a whole.

With 730.2 square miles of land, that is 56 people per square mile (22 per km²), placing Waldo County #1,451 nationally for density and #8 in Maine. The median county equivalent has 47 people per square mile; the Maine median is 51. Put another way, there are about 11 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 Waldo County

Waldo County is divided into 26 cities and towns. In Maine, county subdivisions are local governments, and together they cover all of the county’s land and residents.

The most populous is Belfast city, with 6,988 residents (17.2% of the county). The largest by land is Montville town, at 42.7 mi², or 5.8% of the county’s land. Among those with at least 1,000 residents in 2020, Troy town grew fastest since then (+9.1%).

Population: U.S. Census Bureau Vintage 2025 subcounty estimates, counting only the part of each subdivision inside Waldo County. Land: 2026 Census Gazetteer. How communities are listed.

Metropolitan area

Waldo County is not part of any metropolitan or micropolitan statistical area in the Office of Management and Budget’s July 2023 delineation; 1,306 other county equivalents are also outside one. These areas are built around an urban core of at least 10,000 people plus the counties tied to it by commuting, so counties outside them are generally rural.

ZIP codes

18 ZIP Code Tabulation Areas have land in Waldo County, and each lies mostly inside the county.

043540443804496048480484904915049210492204941049490495104952049730497404981049860498704988

ZIP Code Tabulation Areas are the Census Bureau’s approximations of USPS ZIP Code service areas, from the 2020 Census relationship files. Post-office-box and single-address ZIP Codes have no tabulation area.

Counties bordering Waldo County

Waldo County shares a land border with 6 county equivalents. It has more land than 2 of them. The largest neighbor is Somerset County (3,924.3 mi²) and the smallest is Knox County (364.9 mi²). Together with its neighbors, Waldo County forms a block of 11,327 mi² of land, of which it holds 6.4%.

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

Waldo County has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 1.4 times as much. Maine’s county land could hold about 42 areas the size of Waldo County.

Another way to picture it: the same land area would fill a square about 27 miles (43.5 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 Waldo County?

Waldo County has more land than 2,009 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 Waldo County at #1,056 nationally by total area, 157 places closer to the top than its land rank. The water assigned to this geography moves it ahead of some county equivalents with more land.

Its water share is 15.5%, compared with a national county-equivalent median of 1.2% — 14.4 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 Waldo 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.