WV · GEOID 54055

Mercer County area

Mercer County, West Virginia covers 420.7 square miles: 419 square miles of land and 1.7 square miles of water.

Official Census measurements2026 Gazetteer · retrieved September 27, 2026
Land area419 mi²
Water area1.7 mi²
Total area420.7 mi²
National land rank#2417

County outline

Generalized outline of Mercer County, West Virginia
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 Mercer County is located

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

Area breakdown

Land accounts for 99.6% of Mercer County’s measured area and water for 0.4%. Its combined area converts to 1,089.5 square kilometers or approximately 269,233 acres.

Green: land · blue: water

MeasurementSquare milesSquare kilometersAcres
Land419.0131,085.239268,168.3
Water1.6644.311,065
Total420.6771,089.548269,233.3

How Mercer County compares

By original Census land area, Mercer County ranks #28 of 55 in West Virginia and #2417 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.

Its land area is 1 times the West Virginia county-equivalent median of 419 square miles. It accounts for 1.7% of the combined county land area in the state.

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

What stands out about Mercer County?

Mercer County has more land than 805 of the other 3,221 county equivalents in the dataset.

Land area compared with the typical county equivalent
Mercer County419 mi²
West Virginia median419 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 Mercer County at #2,489 nationally by total area, 72 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 0.4%, compared with a national county-equivalent median of 1.2% — 0.8 percentage points lower. 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 Mercer County in the national ranking. They can be in different states and are not necessarily geographic neighbors.

Land rankCounty equivalentLand mi²Comparison
#2416Tucker County, West Virginia419Compare
#2417Mercer County, West Virginia419This county
#2418Clinton County, Missouri418.9Compare

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 37.403448, -81.106456. 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: 1,085,238,569 m²; AWATER: 4,309,945 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 Mercer County?

The land measurement converts to approximately 268,168 acres. Including water, total area is approximately 269,233 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