Glacier Bay National Park and Preserve constitutes two official park units jointly managed by the National Park Service in the Alaska panhandle west of Juneau. President Calvin Coolidge first proclaimed the area around Glacier Bay a national monument under the Antiquities Act on February 25, 1925. Similarly ANILCA set aside 57,000 additional acres (230.7 km²) of public land for Glacier Bay National Preserve located to the immediate northwest of the park in order to protect a portion of the Alsek River and related fish and wildlife habitats.