McMullen County area

McMullen County, Texas covers 1,156.8 square miles: 1,139.8 square miles of land and 17 square miles of water. Its county seat is Tilden. An estimated 544 people lived there in 2025.

Official Census measurements · GEOID 483112026 Gazetteer · retrieved September 27, 2026
Land area1,139.8 mi²
Water area17 mi²
Population (2025)544
People per mi²0.48

County outline

Generalized outline of McMullen County, Texas
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 McMullen County is located

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

Area breakdown

Land accounts for 98.5% of McMullen County’s measured area and water for 1.5%. Its combined area converts to 2,996.1 square kilometers or approximately 740,340 acres.

Green: land · blue: water

MeasurementSquare milesSquare kilometersAcres
Land1,139.7992,952.066729,471.4
Water16.98343.98610,869.1
Total1,156.7822,996.052740,340.5

How McMullen County compares

By original Census land area, McMullen County ranks #43 of 254 in Texas and #546 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.

Its land area is 1.254 times the Texas county-equivalent median of 908.7 square miles. It accounts for 0.4% of the combined county land area in the state.

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

Population and density of McMullen County

The Census Bureau estimates that 544 people lived in McMullen County on July 1, 2025. That ranks #3,215 of 3,222 county equivalents nationally and #251 of 254 in Texas. Since the April 1, 2020 estimates base of 601, the population has declined by 57 (−9.5%), compared with +8.8% for Texas as a whole.

With 1,139.8 square miles of land, that is 0.48 people per square mile (0.18 per km²), placing McMullen County #3,196 nationally for density and #250 in Texas. The median county equivalent has 47 people per square mile; the Texas median is 22. Put another way, there are about 1,341 acres of land per resident.

Estimated population, 2020–2025 · line scaled to this county’s own range
July 1202020212022202320242025
Estimate598594574577558544
Change—−4−20+3−19−14

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 McMullen County

McMullen County has no incorporated cities, towns or villages. All 544 of its residents live in unincorporated communities, which the Census Bureau describes as census-designated places rather than municipalities.

Metropolitan area

McMullen 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

7 ZIP Code Tabulation Areas have land in McMullen County; 2 of them have most of their land inside the county, and the others mainly cover neighboring areas.

78007780217802278026780717807278075

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 McMullen County

McMullen County shares a land border with 4 county equivalents. It has more land than 1 of them. The largest neighbor is Duval County (1,793.5 mi²) and the smallest is Live Oak County (1,039.7 mi²). Together with its neighbors, McMullen County forms a block of 6,679.2 mi² of land, of which it holds 17.1%.

Map of McMullen County and the 4 county equivalents that border it La Salle County, Texas: 1,486.7 mi² landLive Oak County, Texas: 1,039.7 mi² landAtascosa County, Texas: 1,219.5 mi² landDuval County, Texas: 1,793.5 mi² land
McMullen County (dark) and its bordering county equivalents. Select a neighbor to open its profile. Drawn from the 2025 Census cartographic boundaries in an equal-area projection. How borders are determined.
Bordering county equivalentLand mi²Size vs. McMullenCompare
Duval County1,793.51.6× largerCompare
La Salle County1,486.71.3× largerCompare
Atascosa County1,219.51.1× largerCompare
Live Oak County1,039.71.1× smallerCompare

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

McMullen County has more land than 1 of the 50 states. It is about 1.1 times the land area of Rhode Island (1,033.9 mi²), while Delaware, the next larger state, has 1.7 times as much land (1,948.6 mi²). Texas’s county land could hold about 229 areas the size of McMullen County.

Land area: McMullen County and the closest-sized states
Rhode Island1,033.9 mi²
McMullen County1,139.8 mi²
Delaware1,948.6 mi²

Another way to picture it: the same land area would fill a square about 33.8 miles (54.3 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 McMullen County?

McMullen County has more land than 2,676 of the other 3,221 county equivalents in the dataset.

Land area compared with the typical county equivalent
McMullen County1,139.8 mi²
Texas median908.7 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 McMullen County at #614 nationally by total area, 68 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 1.5%, compared with a national county-equivalent median of 1.2% — 0.3 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 McMullen County in the national ranking. They can be in different states and are not necessarily geographic neighbors.

Land rankCounty equivalentLand mi²Comparison
#545Roger Mills County, Oklahoma1,141.1Compare
#546McMullen County, Texas1,139.8This county
#547McPherson County, South Dakota1,136.7Compare

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 28.384922, -98.578853. 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: 2,952,066,564 m²; AWATER: 43,985,124 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 big is McMullen County?

McMullen County, Texas has 1,139.8 square miles (2,952.1 km²) of land and 17 square miles of water, for a total area of 1,156.8 square miles. It ranks #546 of 3,222 U.S. county equivalents by land area.

Is McMullen County the largest county in Texas?

No. McMullen County ranks #43 of 254 in Texas by land area. The largest is Brewster County, with 6,183.8 square miles of land.

What counties border McMullen County?

McMullen County shares a land border with La Salle County, Live Oak County, Atascosa County, and Duval County.

What is the population of McMullen County?

The Census Bureau estimates McMullen County had 544 residents on July 1, 2025, ranking #3,215 of 3,222 county equivalents. That is 0.48 people per square mile of land.

What is the county seat of McMullen County?

The county seat of McMullen County is Tilden.

Is McMullen County part of a metropolitan area?

No. McMullen County is outside every metropolitan and micropolitan statistical area in the July 2023 OMB delineation.

How many ZIP codes are in McMullen County?

7 ZIP Code Tabulation Areas have land in McMullen County, and 2 of them have most of their land inside the county. Census ZIP Code Tabulation Areas approximate USPS ZIP Code areas.

How does McMullen County compare with U.S. states?

It has more land than 1 of the 50 states, including Rhode Island (1,033.9 square miles of land).

How many acres of land are in McMullen County?

The land measurement converts to approximately 729,471 acres. Including water, total area is approximately 740,340 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

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