Lassen County area

Population and density of Lassen County

The Census Bureau estimates that 28,117 people lived in Lassen County on July 1, 2025. That ranks #1,549 of 3,222 county equivalents nationally and #48 of 58 in California. Since the April 1, 2020 estimates base of 32,729, the population has declined by 4,612 (−14.1%), compared with −0.5% for California as a whole.

With 4,541.4 square miles of land, that is 6.2 people per square mile (2.4 per km²), placing Lassen County #2,797 nationally for density and #52 in California. The median county equivalent has 47 people per square mile; the California median is 112. Put another way, there are about 103 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 Lassen County

1 incorporated place lies at least partly in Lassen County. Together they are home to 12,816 people (45.6%); the other 15,301 (54.4%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Susanville city, with 12,816 residents in the county.

Metropolitan area

Lassen County is a central county of the Susanville, CA Micropolitan Statistical Area. Lassen County is the area’s only county equivalent, so the micro area has the same 4,541.4 square miles of land. By combined land it ranks #28 of 542 micropolitan areas, and #455 by population.

ZIP codes

18 ZIP Code Tabulation Areas have land in Lassen County; 16 of them have most of their land inside the county, and the others mainly cover neighboring areas.

960069600996056960689610596109961109611396114961179611996121961239612896130961329613696137

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 Lassen County

Lassen County shares a land border with 5 county equivalents, including 1 in Nevada. It has more land than 4 of them. The largest neighbor is Washoe County (6,315.9 mi²) and the smallest is Sierra County (953.2 mi²). Together with its neighbors, Lassen County forms a block of 22,087.4 mi² of land, of which it holds 20.6%.

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

Lassen County has more land than 2 of the 50 states. It is about 2.3 times the land area of Delaware (1,948.6 mi²), while Connecticut, the next larger state, has 1.1 times as much land (4,842.5 mi²). California’s county land could hold about 34 areas the size of Lassen County.

Another way to picture it: the same land area would fill a square about 67.4 miles (108.5 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 Lassen County?

Lassen County has more land than 3,124 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 Lassen County at #102 nationally by total area, 4 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 3.8%, compared with a national county-equivalent median of 1.2% — 2.6 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 Lassen County 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.