Surprise Lake

lake, Alaska, United States

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July 14, 2026

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Surprise Lake is a lake located within the Aniakchak National Monument and Preserve in southwestern Alaska, United States. This lake is situated at the bottom of a large, dry caldera, which is part of the volcanically active Aleutian Range. The volcano last erupted in 1931. Surprise Lake's water drains through a rift in the crater wall, forming the Aniakchak River, which is designated as a national wild river. Access to this remote area is typically by float plane.1

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Aniakchak National Monument and Preserve
…cones, and, at its bottom, Surprise Lake. A 1,500-foot (450-metre) rift in the crater wall allows the lake’s water to drain, the flow forming the Aniakchak River. Access to the area is by float plane; raft trips also are made on the Aniakchak, which is designated a national wild river.
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…cones, and, at its bottom, Surprise Lake. A 1,500-foot (450-metre) rift in the crater wall allows the lake’s water to drain, the flow forming the Aniakchak River. Access to the area is by float plane; raft trips also are made on the Aniakchak, which is designated a national wild river.
Read More