Alaska, with a land area one-fifth the size of the conterminous US, ranked 47th in population in 2002 with an estimated total of 643,786, an increase of 2.7% since 2000. Between 1990 and 2000, Alaska's population grew from 550,043 to 626,932, or 14%.

Population projections for 2005 reach 700,000, and the state is projected to have a population of 885,000 by 2025. Regions of settlement and development constitute less than 1% of Alaska's total land area. The population density was 1.1 persons per sq mi in 2000, making Alaska the nation's most sparsely settled state.

Historically, population shifts in Alaska have directly reflected economic and political changes. The Alaska gold rush of the 1890s resulted in a population boom from 32,052 in 1890 to 63,592 a decade later; by the 1920s, however, when mining had declined, Alaska's population had decreased to 55,036. The region's importance to US national defense during the 1940s led to a rise in population from 72,524 to 128,643 during that decade. Oil development, especially the construction of the Alaska pipeline, brought a 78% population increase between 1960 and 1980. Almost all of this gain was from migration.

The state's population is much younger than that of the nation as a whole. The median age was 32.4 in 2000, compared with the national average of 35.3, and only 5.7% of all Alaskans were 65 years of age or older—by far the lowest such percentage in any state—while 30.4% were under 18 years old (compared with the national average of 25.7). Alaska is one of the few states where men outnumber women; as of 2000 men accounted for 51.7% of Alaskan residents.

About half of Alaska's residents live in and around Anchorage, whose population was estimated at 268,983 in 2002. The 2001 estimated populations of other leading metropolitan areas were Fairbanks, 83,694, and Juneau, 30,558. Less than a quarter of the population lives in Western Alaska.