Buldir Island (also sometimes written Buldyr; Aleut: Idmaax[1]) is a small island in the western Aleutian Islands of the U.S. state of Alaska. It lies midway between the Near Islands in the West and the Rat Islands in the East.
The island is small, with an area of just 7.4482 square miles (19.291 km2). It is 4.3 miles (6.9 km) long and 2.5 miles (4.0 km) wide. There was no human population reported by the 2000 census. The two major volcanoes on the island are the Buldir Volcano, which forms most of the island, and the East Cape Volcano, which forms the island's northeast section. Buldir Volcano is the taller, reaching 2,152 feet (656 m) in height, the highest point on the island. The coastlines along the island are often tall steep cliffs.
The island is home to 21 species of breeding seabirds, making it the most diverse seabird colony in the Northern Hemisphere. The island's colonies include Crested Auklets and Least Auklets, as well as puffins, storm-petrels and other species. It is one of only four locations in the world where Red-legged Kittiwakes breed.