Walter Wirth Lake (aka Lake Wirth) is a lake in Salem, Oregon, United States. Walter Wirth Lake is wholly contained within Cascades Gateway Park. The park and lake began development in 1957 with the Salem Area Chamber of Commerce working with the State Highway Department to convert a gravel burrow pit into a park. Original development of the park included a swimming area, paddle boats, a children's zoo, and concession stands. In 1976 a Department of Environmental Quality study determined the lake to be suffering the effects from upstream polluters closing the lake to swimming.