Alexander Lake is a lake in South Central Alaska, located at head of Alexander Creek (Susitna River), 46 miles (74 km) North of Tyonek, Alaska on Cook Inlet Low.

Alexander Creek (Susitna River) in turn drains into Cook Inlet on the Pacific Ocean.

According to the Alaska Department of Fish and Game, Alexander Lake is known by Alaskan Natives for its Tree Squirrel population, calling it "Deldida Bena", (Tree Squirrel Lake).

Alexander Lake reported in 1926 by Capps (1935, pl. 1), United States Geological Survey.

Probably derived from Alexander Creek (Susitna River) which drains the lake.

Alexander Lake is also known as Deldida Bena ("Tree Squirrel Lake") by Alaska Natives.

• List of lakes of Alaska