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.
Alaska State Archives. This is an Archives in the old fashioned sense, focusing on records management procedures for the state, and keeping most of its collection in file drawers. Its online collection is rather small, but does include one sizable document of note, the Probate Records of Alaska, 1885-1960...a names list of 17,000 probate cases from Alaska's early court system.
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.
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: