Glenn County area

Glenn County, California covers 1,327 square miles: 1,313.9 square miles of land and 13 square miles of water. Its county seat is Willows. An estimated 28,141 people lived there in 2025.

Official Census measurements · GEOID 060212026 Gazetteer · retrieved September 27, 2026
Land area1,313.9 mi²
Water area13 mi²
Population (2025)28,141
People per mi²21

County outline

Generalized outline of Glenn County, California
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 Glenn County is located

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

Area breakdown

Land accounts for 99% of Glenn County’s measured area and water for 1%. Its combined area converts to 3,436.9 square kilometers or approximately 849,273 acres.

Green: land · blue: water

MeasurementSquare milesSquare kilometersAcres
Land1,313.943,403.089840,921.6
Water13.04933.7978,351.4
Total1,326.9893,436.886849,273

How Glenn County compares

By original Census land area, Glenn County ranks #36 of 58 in California and #454 of 3,222 nationally. National rankings include the 50 states, District of Columbia, and Puerto Rico.

Its land area is 0.856 times the California county-equivalent median of 1,535.7 square miles. It accounts for 0.8% of the combined county land area in the state.

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

Population and density of Glenn County

The Census Bureau estimates that 28,141 people lived in Glenn County on July 1, 2025. That ranks #1,548 of 3,222 county equivalents nationally and #47 of 58 in California. Since the April 1, 2020 estimates base of 28,910, the population has declined by 769 (−2.7%), compared with −0.5% for California as a whole.

With 1,313.9 square miles of land, that is 21 people per square mile (8.3 per km²), placing Glenn County #2,274 nationally for density and #47 in California. The median county equivalent has 47 people per square mile; the California median is 112. Put another way, there are about 30 acres of land per resident.

Estimated population, 2020–2025 · line scaled to this county’s own range
July 1202020212022202320242025
Estimate28,88928,68928,36328,16828,32028,141
Change—−200−326−195+152−179

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 Glenn County

2 incorporated places lie at least partly in Glenn County. Together they are home to 14,497 people (51.5%); the other 13,644 (48.5%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Orland city, with 8,381 residents in the county. The county seat, Willows city, has 6,116 residents. Among places with at least 1,000 residents in 2020, Orland city grew fastest since then (+1%).

Incorporated placePopulation 2025Since 2020Land mi²
Orland city8,381+1%3.046
Willows cityCounty seat6,116−2.9%2.836

Population: U.S. Census Bureau Vintage 2025 subcounty estimates, counting only the part of each place inside Glenn County. Land: 2026 Census Gazetteer, for the whole place even where it extends into other counties. How communities are listed.

Metropolitan area

Glenn 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

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

9591395920959399594395951959639597095988

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 Glenn County

Glenn County shares a land border with 5 county equivalents. It has more land than 2 of them. The largest neighbor is Mendocino County (3,506.8 mi²) and the smallest is Colusa County (1,150.6 mi²). Together with its neighbors, Glenn County forms a block of 11,812.1 mi² of land, of which it holds 11.1%.

Map of Glenn County and the 5 county equivalents that border it Tehama County, California: 2,949.1 mi² landColusa County, California: 1,150.6 mi² landButte County, California: 1,636.5 mi² landLake County, California: 1,255.1 mi² landMendocino County, California: 3,506.8 mi² land
Glenn 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. GlennCompare
Mendocino County3,506.82.7× largerCompare
Tehama County2,949.12.2× largerCompare
Butte County1,636.51.2× largerCompare
Lake County1,255.1about the sameCompare
Colusa County1,150.61.1× smallerCompare

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

Glenn County has more land than 1 of the 50 states. It is about 1.3 times the land area of Rhode Island (1,033.9 mi²), while Delaware, the next larger state, has 1.5 times as much land (1,948.6 mi²). California’s county land could hold about 119 areas the size of Glenn County.

Land area: Glenn County and the closest-sized states
Rhode Island1,033.9 mi²
Glenn County1,313.9 mi²
Delaware1,948.6 mi²

Another way to picture it: the same land area would fill a square about 36.2 miles (58.3 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 Glenn County?

Glenn County has more land than 2,768 of the other 3,221 county equivalents in the dataset.

Land area compared with the typical county equivalent
Glenn County1,313.9 mi²
California median1,535.7 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 Glenn County at #518 nationally by total area, 64 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%, compared with a national county-equivalent median of 1.2% — 0.2 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 Glenn County in the national ranking. They can be in different states and are not necessarily geographic neighbors.

Land rankCounty equivalentLand mi²Comparison
#453Becker County, Minnesota1,315Compare
#454Glenn County, California1,313.9This county
#455Ontonagon County, Michigan1,311Compare

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 39.602546, -122.401700. 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: 3,403,088,094 m²; AWATER: 33,796,766 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 Glenn County?

Glenn County, California has 1,313.9 square miles (3,403.1 km²) of land and 13 square miles of water, for a total area of 1,327 square miles. It ranks #454 of 3,222 U.S. county equivalents by land area.

Is Glenn County the largest county in California?

No. Glenn County ranks #36 of 58 in California by land area. The largest is San Bernardino County, with 20,068.4 square miles of land.

What counties border Glenn County?

Glenn County shares a land border with Tehama County, Colusa County, Butte County, Lake County, and Mendocino County.

What is the population of Glenn County?

The Census Bureau estimates Glenn County had 28,141 residents on July 1, 2025, ranking #1,548 of 3,222 county equivalents. That is 21 people per square mile of land.

What is the county seat of Glenn County?

The county seat of Glenn County is Willows.

What cities and towns are in Glenn County?

Glenn County has 2 incorporated places. The most populous are Orland city and Willows city; 13,644 residents live outside any incorporated place.

Is Glenn County part of a metropolitan area?

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

How many ZIP codes are in Glenn County?

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

How does Glenn 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 Glenn County?

The land measurement converts to approximately 840,922 acres. Including water, total area is approximately 849,273 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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