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Fremont County Museum System

Asmus Boysen and the Dam

Asmus Boysen, the man for whom Boysen State Park and Boysen Dam is named, was born in Denmark and moved to America when he was about 18 years old. He eventually settled in Illinois and married a wealthy woman. He later moved to Iowa and become a multi-millionaire by investing wisely in real estate and banking interests. At the age of 31 he was elected as a Representative to the Iowa General Assembly. He had nine children with his wife Anna; however, only 4 of them would survive into adulthood.


Asmus loved a good challenged and was always working on something new. His adventurous side took him to the “Wild West” where he would spend a period of time exploring and looking for coal. News of Asmus Boysen, and his plans to mine for coal and minerals, soon spread around the state of Wyoming and even into Colorado. Rumors started flying and the story was picked up through the Lander Clipper newspaper in April of 1899. The Boysen story eventually made its way to the Cheyenne Tribune in May 1899 and even to the Denver News later that same year.


Due in part to his political connections Asmus would eventually lease out about 78,000 acres in 1899 from the Shoshone and Arapaho tribes. Asmus had found the challenge of a lifetime. The official paperwork was signed in July of 1899 and approved on October 4th, 1899 giving Asmus mining rights to coal on the tribal lands. 


Soon after leasing the land, Asmus built a home for his family on the west side of the gorge and moved his family from Iowa to join him. Once they were settled he incorporated the Asmus Boysen Mining Company, which was valued at $5 million. He also thought that there would be enough energy generating from the dam to serve a verity of needs by the local communities that might be interested in purchasing his access to electricity.  


Asmus was a man ahead of his time and saw building the dam as an investment in the future and in electrical power. The cost of building had cost him nearly $2 million for the dam and power plant. As Asmus predicted his dam not only benefited him in his mining activities but also the towns of Shoshoni and Riverton for nearly twenty years.


The Burlington Railroad soon followed after, through the Wind River canyon, building tracks above the dam. Unfortunately, flash floods that are common in the area caused large amounts of silt to build up in the narrow channel behind the dam. Later, the railroad sued Boysen for the removal of the dam because the rising waters were considered a threat to the tracks. Boysen ultimately lost the suit, and the dam was removed, with the last of it being demolished in 1948. A newer dam, carrying the same name, was built further upstream in 1951, replacing the original dam.


Not much is known about Asmus Boysen in his later years. There were some controversies regarding his mining operations and a diamond drill in 1905. However, even in his struggles the public still held him in high regard and when he was sent an anonymous letter suggesting he leave town, the people of Thermopolis rallied in a public protest to show their support.

Next up for the Fremont County Museums


June 9th, 9-3pm at the Dubois Museum, “New Life at Pete’s Pond”

              McDonald’s Children’s Exploration Series

June 9th, 1pm at the Pioneer Museum, “Gold Panning Day”

              McDonald’s Children’s Exploration Series

June 9th, 2pm at the Riverton Museum, “Plant a Seed: Ag in Fremont County”

              McDonald’s Children’s Exploration Series

June 16th, 10am at the Pioneer Museum, “Miner’s Delight Adventure Trek”

Wind River Visitors Council Adventure Trek Series

June 16th, 9am at the Dubois Museum, “Laval Creek Tie Hack Adventure Trek”

              Wind River Visitors Council Adventure Trek Series


The Dubois Museum, the Pioneer Museum in Lander and the Riverton Museum work extremely hard to provide programs, care for the facilities, create exhibits and care for the thousands of artifacts and archival documents in the collections of the museums. In order to consistently accomplish these objectives the museums are more reliant than ever on donations from the private sector. Please make your tax deductible contribution to be used specifically for the benefit of the museum of your choosing by sending a check to Fremont County Museums 450 N 2nd Rm 320 or taking it directly to the museum you choose to support.