St. John the Baptist Parish area

Population and density of St. John the Baptist Parish

The Census Bureau estimates that 39,875 people lived in St. John the Baptist Parish on July 1, 2025. That ranks #1,214 of 3,222 county equivalents nationally and #27 of 64 in Louisiana. Since the April 1, 2020 estimates base of 42,477, the population has declined by 2,602 (−6.1%), compared with −0.9% for Louisiana as a whole.

With 214.5 square miles of land, that is 186 people per square mile (72 per km²), placing St. John the Baptist Parish #669 nationally for density and #11 in Louisiana. The median county equivalent has 47 people per square mile; the Louisiana median is 48. Put another way, there are about 3.4 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. John the Baptist Parish

St. John the Baptist Parish has no incorporated cities, towns or villages. All 39,875 of its residents live in unincorporated communities, which the Census Bureau describes as census-designated places rather than municipalities.

Metropolitan area

St. John the Baptist Parish is a central county of the New Orleans-Metairie, LA Metropolitan Statistical Area. Its 7 county equivalents have 970,849 residents on 2,358.6 square miles of land; St. John the Baptist Parish accounts for 9.1% of the land and 4.1% of the residents. By combined land it ranks #139 of 393 metropolitan areas, and #60 by population. It belongs to the New Orleans-Metairie-Slidell, LA-MS Combined Statistical Area.

ZIP codes

6 ZIP Code Tabulation Areas have land in St. John the Baptist Parish; 5 of them have most of their land inside the county, and the others mainly cover neighboring areas.

700497005170068700767008470090

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. John the Baptist Parish

St. John the Baptist Parish shares a land border with 8 county equivalents. Each of them has more land than St. John the Baptist Parish. The largest neighbor is Lafourche Parish (1,069.7 mi²) and the smallest is St. James Parish (237.9 mi²). Together with its neighbors, St. John the Baptist Parish forms a block of 4,675.3 mi² of land, of which it holds 4.6%.

How big is St. John the Baptist Parish compared with U.S. states?

St. John the Baptist Parish has less land than any of the 50 states. Rhode Island, the smallest state by land area, has 1,033.9 mi², about 4.8 times as much. Louisiana’s county land could hold about 202 areas the size of St. John the Baptist Parish.

Another way to picture it: the same land area would fill a square about 14.6 miles (23.6 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 St. John the Baptist Parish?

St. John the Baptist Parish has more land than 245 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. John the Baptist Parish at #2,546 nationally by total area, 431 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 47.7%, compared with a national county-equivalent median of 1.2% — 46.5 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. John the Baptist Parish 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.