Peter DesRosier, son of Joseph and Dorothy (Pepin) DesRosier of Rhode Island, was born on January 9, 1873. He was educated in Providence, Rhode Island, and moved to Havre, Montana, in 1892, where he was employed by the Broadwater and Pepin Company. In 1900 he formed the DesRosier Newman Mercantile Company. By 1903 he acquired his partner's interest in the company and was sole owner. In 1909 he returned to work for the Broadwater and Pepin Company, managing a trading post on the Blackfeet Reservation at Browning. After several years managing the trading post, DesRosier again formed his own business, the DesRosier Drug Store. In addition, he was postmaster at Browning from 1915 until 1921 and raised cattle on the Blackfeet Reservation. DesRosier also founded a theater in Browning. He was a member of several different fraternal organizations. Peter DesRosier married Emma Jane McIntyre, daughter of Patrick James and Margaret (Martin) McIntyre of Havre, on April 27, 1891. Emma Jane DesRosier was active in several community activities in Browning, including the American Red Cross and the Women's Club. Peter and Emma Jane DesRosier had four children: I. Lauretta Mary (DesRosier) Leadbetter, Peter LeRoy, J. Stuart, and Patricia Alouise (DesRosier) McCourt. Peter DesRosier died on December 29, 1932. Peter LeRoy DesRosier was born on April 4, 1902, in Havre, Montana. He worked as a customs inspector, deputy game warden, and was the subsequent owner of Glacier Drug Company in Browning. During World War II he served with the 79th Battalion of the U.S. Navy, the Seabees. He was married to Mary Freda Campbell (1898-1961), daughter of Fred Choteau Campbell.