St. Lawrence County area

Population and density of St. Lawrence County

The Census Bureau estimates that 105,488 people lived in St. Lawrence County on July 1, 2025. That ranks #602 of 3,222 county equivalents nationally and #27 of 62 in New York. Since the April 1, 2020 estimates base of 108,505, the population has declined by 3,017 (−2.8%), compared with −1% for New York as a whole.

With 2,679.5 square miles of land, that is 39 people per square mile (15 per km²), placing St. Lawrence County #1,766 nationally for density and #57 in New York. The median county equivalent has 47 people per square mile; the New York median is 112. Put another way, there are about 16 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 St. Lawrence County

St. Lawrence County is divided into 33 cities and towns. In New York, county subdivisions are local governments, and together they cover all of the county’s land and residents.

The most populous is Potsdam town, with 14,367 residents (13.6% of the county). The largest by land is Colton town, at 241.7 mi², or 9% of the county’s land. The county seat, Canton town, has 11,256 residents. Among those with at least 1,000 residents in 2020, De Peyster town grew fastest since then (+3.1%).

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

Metropolitan area

St. Lawrence County is a central county of the Massena-Ogdensburg, NY Micropolitan Statistical Area. St. Lawrence County is the area’s only county equivalent, so the micro area has the same 2,679.5 square miles of land. By combined land it ranks #57 of 542 micropolitan areas, and #29 by population.

ZIP codes

54 ZIP Code Tabulation Areas have land in St. Lawrence County; 45 of them have most of their land inside the county, and the others mainly cover neighboring areas.

128471291412922129271293012965129671297312980129861360813613136141361713621136231362513630136331363513639136421364513646136471364813649136521365413658136601366213664136661366713668136691367013672136761367813679136801368113683136841368713690136911369413695136961369713699

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 St. Lawrence County

St. Lawrence County shares a land border with 5 county equivalents. It has more land than every one of them. The largest neighbor is Hamilton County (1,717.4 mi²) and the smallest is Jefferson County (1,267.9 mi²). Together with its neighbors, St. Lawrence County forms a block of 9,981 mi² of land, of which it holds 26.8%.

How big is St. Lawrence County compared with U.S. states?

St. Lawrence County has more land than 2 of the 50 states. It is about 1.4 times the land area of Delaware (1,948.6 mi²), while Connecticut, the next larger state, has 1.8 times as much land (4,842.5 mi²). New York’s county land could hold about 18 areas the size of St. Lawrence County.

Another way to picture it: the same land area would fill a square about 51.8 miles (83.3 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 St. Lawrence County?

St. Lawrence County has more land than 3,027 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 St. Lawrence County at #198 nationally by total area, 3 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 5%, compared with a national county-equivalent median of 1.2% — 3.9 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 St. Lawrence 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.