Alder Lake is a 7 mi (11 km) long reservoir on the Nisqually River in Eatonville, Washington in the U.S. state of Washington, which was created by the construction of Alder Dam by Tacoma Power in September 1944.

At the very eastern end of the lake is the town of Elbe, Washington.

[3] The extinct town, in turn, was named for alder trees near the original site.

[4] The current community of Alder is located north of the lake.

In 2021, Intel named its new microarchitecture after Alder Lake.