I suppose when a state is as big as Alaska, it needs more than one place for its archives. Alaska has three archive collections, at the state government, the state library, and the state university. You need a hunting license to find them all.
For family history researchers, the rest of the Archives collection can be a valuable resource, even though the bulk of their materials are offline. See their Alaska Genealogy page for a description of what's available, and procedures for requesting information.
Behind door #2, you can find Alaska's Digital Archives, from the University of Alaska, with a wealth of historical photographs, albums, oral histories, moving images, maps, documents, physical objects, tribal histories, and other materials from libraries, museums, tribes, villages and archives throughout the state.
Materials here are divided into two broad areas, Native Cultures, and Alaska Statehood:
Pathways for Alaska Native Materials includes categories for:
The materials can also be browsed by Region or by Timeline.
Pathways for Movement to Statehood Materials include:
Lastly, we have the Online Resources of the Alaska State Historical Library. Their collection includes a number of indexes, which largely consist of names of people and an indication of where to find more information. For example, the Index for Biographies of Alaska-Yukon Pioneers, 1850-1950, v. 1-5, (opens as a Word document) includes many thousands of names, with a pointer to offline records.
Other Indexes & Guides include:
You'll also find links to some very nice Photo Collections, Online Exhibits, & Teaching Tools:
Alaska at War!
Schools in Rural Alaska
Alaskan Photo Mystery! (identify the mystery photos!)
Alaska Purchase Centennial Collection: a historical survey in pictures
Gold Rush Centennial Photographs, 1893 - 1916
Eight Stars of Gold...The story of Alaska's flag