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Boysen State Park

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About Our Site - Boysen State Park


The first white men through the Wind River Canyon were the Ashley Fur Party in 1825. The original dam was built by Asmus Boysen in 1908, for whom the park and reservoir are named. Part of the original dam can still be seen adjacent to the tunnels on the Lower Wind River Campground. Mr. Boysen also built a 710kW power plant at the site. Operations ceased when in 1923 a major flood filled the plant with silt.

The CB&O Railroad went through the canyon in 1911 and the state highway went through in 1925. The existing dam was completed in 1951. Boysen became a state park in 1956.

Original-Boysen-Dam-SiteLower-Wind-River-CampgroundOriginal Asmus Boysen Dam Site Located just north of the Lower Wind River Campground. This site also represents the park's northern boundary.


Water Quality Advisory in Effect at Boysen Reservoir


Contact: John Bass, Superintendent, Boysen State Park
307-876-2796,  john.bass@wyo.gov

The Wyoming Department of Environmental Quality has issued an advisory for the North Marina at Boysen Reservoir, more commonly known as the Brannon Boat Ramp. Toxic algae are present in the water at that location.  John Bass, Superintendent of Boysen State Park said, “While it is a common occurrence and should not deter visitors from enjoying other areas of the park, we want to ensure the public’s safety.” The advisory recommends that visitors do not swim, drink water, rinse fish or allow pets to come into contact with the water in the affected area. No other areas of the park are affected at this time. These advisories will be updated on social media and posted in the park. Visitors can get more information at wyoparks.org@wyomingStateParks and @BoysenStatePark on facebook.

For more information on Harmful Algal Blooms (HAB), visit DEQ.Wyoming.Gov  

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Wyoming State Parks, Historic Sites & Trails
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More Information - Boysen State Park



Facts and Figures
  • Current Dam
  • Structural height: 216 feet
  • Crest Length: 1,100 feet
  • Type: rolled earth, rock-fill
  • Volume of material: 1,700,000 cubic yards
  • Spillway capacity: 20,000 cubic feet/seconds
  • Power plant: 15,000 kw

Reservoir and park

  • Water: 19,560 acres
  • Shoreline: 76 miles
  • Length: 20 miles
  • Widest point: 5.5 miles
  • Land: 15,145

Believe it or not…

Yes! Contrary to what your eyes tell you, the Wind River flows NORTH!




Site Status


 We are open! Please view our hours below to find a good time to visit!

***North Marina at Boysen Reservoir, commonly known as the Brannon Boat Ramp, is under a water quality advisory.** See "News & Updates" this page.




Grounds open all year - 24 hours.


Park grounds are open year-round, weather permitting.

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