The dam was constructed between 1947 and 1952 at the mouth of Wind River Canyon, just upstream from a previous dam that had been built by Asmus Boysen in 1908 on land he had leased from the Shoshone and Arapaho tribes.

The dam and much of the reservoir are physically located on the Wind River Indian Reservation.

As a result of construction of the dam a major railroad track that connected Billings, Montana with Casper, Wyoming was flooded.

Boysen Marina sits near the shore on the northeast side of the reservoir and has a bait shop and cafe and offers boat and jet ski rentals.

Boysen Reservoir has a cold-semi arid climate with vast temperature differences throughout the year from summers averaging highs in the low 90s to winters averaging lows in the single digits.