This park was named after Asmus Boysen, who was born in Denmark in 1868. He settled in Illinois. While he was on a mining exploration trip in 1900, he visited the Wind River Canyon and envisaged a dam that could provide electricity to nearby mines, and the water itself could be used for irrigation. He built the dam in 1908 at the mouth of the Wind River, costing two million. Currently, only a small section of the dam is left because floods ruined the turbines and threatened to flood the nearby railroad. Part of the original dam can be seen near the N end of the Lower Wind River Canyon.

Boysen is in the center of Wyoming, 100 miles west of Casper. It covers 40,000 acres, is covered with sagebrush and is relatively dry. The 19,000 acre reservoir offers excellent recreational activities, ice and regular fishing, and wildlife viewing.