Linked from
The 14 pages that link to Alaska Purchase, each with the reason it gives.
AlaskaRelated: The purchase established U.S. sovereignty over the territory that became Alaska.
Alaska PeninsulaRelated: The purchase brought the peninsula under U.S. sovereignty.
Kodiak IslandRelated: The purchase shifted the island from Russian to American rule.
History of AlaskaRelated: The purchase shifted Alaska from Russian possession to U.S. control.