Big Lake is a census-designated place (CDP) in Matanuska-Susitna Borough, Alaska, United States. It is part of the Anchorage, Alaska Metropolitan Statistical Area. The population was determined to be 2,635 at the 2000 census.
According to the United States Census Bureau, the CDP has a total area of 144.8 square miles, of which, 131.9 square miles of it is land and 12.9 square miles of it (8.89%) is water.
The racial makeup of the CDP was 87.13% White Americans, with other races making up the remaining 12.87%.