Lake Ralphine is a reservoir in Howarth Memorial Park in the city of Santa Rosa, in the U.S. state of California.

The California Department of Fish and Wildlife stocks the lake annually with trout of catchable size.

[3] Other fishes found in the lake include bass, bluegill, and catfish.

[4] The lake is formed by an earthen dam which dates back to 1882.

[2] It was built by Colonel Mark Lindsay McDonald and named after his wife.