This first zooarchaeological analysis for the Islands of Four Mountains (IFM), Aleutian Islands, Alaska, provides data about local hunter-gatherer resource exploitation over three thousand yr. The majority of zooarchaeological material represents faunal resources that were harvested within several kilometers of villages. Our analysis shows that IFM subsistence system was shaped by the small size of these islands, which is mostly true for all of the Aleutian Islands. The archaeological middens indicate that Aleuts readily exploited new resources when they became available, expanding their dietary niche. Despite human harvesting, most faunal populations remained stable; however, Aleuts overexploited the storm-petrel colony on Carlisle Island.