MD · GEOID 24009

Calvert County area

Calvert County, Maryland covers 345.1 square miles: 213.2 square miles of land and 131.9 square miles of water.

Official Census measurements2026 Gazetteer · retrieved September 27, 2026
Land area213.2 mi²
Water area131.9 mi²
Total area345.1 mi²
National land rank#2979

County outline

Generalized outline of Calvert County, Maryland
2025 Census cartographic boundary, fitted to this frame. County maps are not at a common scale. The 2026 area measurements below come from the separate Gazetteer release. Map source and limitations.

Where Calvert County is located

Calvert County highlighted on a map of all U.S. county equivalents. About the maps

Area breakdown

Land accounts for 61.8% of Calvert County’s measured area and water for 38.2%. Its combined area converts to 893.7 square kilometers or approximately 220,848 acres.

Green: land · blue: water

MeasurementSquare milesSquare kilometersAcres
Land213.19552.16136,441.6
Water131.885341.58184,406.4
Total345.075893.74220,848

How Calvert County compares

By original Census land area, Calvert County ranks #23 of 24 in Maryland and #2979 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.

Its land area is 0.509 times the Maryland county-equivalent median of 418.5 square miles. It accounts for 2.2% of the combined county land area in the state.

See the complete Maryland ranking · What counts as a county equivalent?

What stands out about Calvert County?

Calvert County has more land than 243 of the other 3,221 county equivalents in the dataset.

Land area compared with the typical county equivalent
Calvert County213.2 mi²
Maryland median418.5 mi²
National median604.5 mi²

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 Calvert County at #2,745 nationally by total area, 234 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 38.2%, compared with a national county-equivalent median of 1.2% — 37.1 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 Calvert County in the national ranking. They can be in different states and are not necessarily geographic neighbors.

Land rankCounty equivalentLand mi²Comparison
#2978Lyon County, Kentucky213.8Compare
#2979Calvert County, Maryland213.2This county
#2980Northampton County, Virginia211.7Compare

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.

Representative coordinates

The Census internal point is 38.518822, -76.525248. It represents a location inside the geography; it is not necessarily the centroid or the address of a courthouse.

Source and precision

U.S. Census Bureau, 2026 Gazetteer Files, Counties. Original ALAND: 552,158,500 m²; AWATER: 341,580,755 m². Rankings use ALAND; exact ties use ascending GEOID. Tables preserve Census-published square miles to three decimals, with conversions based on those values.

Download the official county source ZIP ↗ · Methodology

Common questions

How many acres of land are in Calvert County?

The land measurement converts to approximately 136,442 acres. Including water, total area is approximately 220,848 acres. One square mile equals 640 acres.

Why might another source show a different area?

Check whether it reports land or total area, its Census vintage, and its rounding. Our guide explains how to reconcile county area figures.

Can this establish a property boundary?

No. Statistical measurements and generalized maps do not establish property lines. Consult the relevant local surveying or land-records authority.

Cite this county

Download the complete CSV or JSON dataset