Petersburg Borough area

Population and density of Petersburg Borough

The Census Bureau estimates that 3,394 people lived in Petersburg Borough on July 1, 2025. That ranks #3,006 of 3,222 county equivalents nationally and #21 of 30 in Alaska. Since the April 1, 2020 estimates base of 3,396, the population has declined by 2 (−0.1%), compared with +0.5% for Alaska as a whole.

With 2,901.6 square miles of land, that is 1.2 people per square mile (0.45 per km²), placing Petersburg Borough #3,133 nationally for density and #12 in Alaska. The median county equivalent has 47 people per square mile; the Alaska median is 0.73. Put another way, there are about 547 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 Petersburg Borough

1 incorporated place lies at least partly in Petersburg Borough. Together they are home to 18 people (0.5%); the other 3,376 (99.5%) live outside any incorporated place, in unincorporated communities and rural areas.

The largest is Kupreanof city, with 18 residents in the county.

Metropolitan area

Petersburg Borough 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

1 ZIP Code Tabulation Area has land in Petersburg Borough, and it lies mostly inside the county.

99833

ZIP Code Tabulation Areas are the Census Bureau’s approximations of USPS ZIP Code service areas, from the 2020 Census relationship files. Post-office-box and single-address ZIP Codes have no tabulation area.

Counties bordering Petersburg Borough

Petersburg Borough shares a land border with 3 county equivalents. It has more land than 1 of them. The largest neighbor is Hoonah-Angoon Census Area (6,560 mi²) and the smallest is Wrangell City and Borough (2,556.3 mi²). Together with its neighbors, Petersburg Borough forms a block of 17,286.1 mi² of land, of which it holds 16.8%.

How big is Petersburg Borough compared with U.S. states?

Petersburg Borough has more land than 2 of the 50 states. It is about 1.5 times the land area of Delaware (1,948.6 mi²), while Connecticut, the next larger state, has 1.7 times as much land (4,842.5 mi²). Alaska’s county land could hold about 197 areas the size of Petersburg Borough.

Another way to picture it: the same land area would fill a square about 53.9 miles (86.7 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 Petersburg Borough?

Petersburg Borough has more land than 3,044 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 Petersburg Borough at #137 nationally by total area, 41 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 24.2%, compared with a national county-equivalent median of 1.2% — 23 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 Petersburg Borough 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.