Rosetta Elliot McMahon was born in McMechen, West Virginia, in September of 1920. She graduated from Union High School in Benwood, West Virginia, in 1938. She then worked as a server in the tea room of a local college and later went to work at the Continental Can Company, which had begun defense manufacturing.
McMahon enlisted in the U.S. Navy WAVES on October 2, 1942. She completed basic training at Indiana University and in February 1943 was assigned to the Bureau of Supplies and Accounts in Washington, D.C. While stationed there she worked as a typist. She married Chester McMahon, a serviceman she had met in West Virginia, in October 1943. She was discharged on 4 March 1944 due to pregnancy.
After leaving the service, McMahon returned to McMechen, West Virgina. When her husband reenlisted in the air force, she traveled with him to each of his assignments. During this time she worked as a typist at Amarillo Air Force Base, in a daycare at Niagara Falls, and at the MacDill Air Force Base visitor's center. She also volunteered with the Red Cross and served Girl Scout troop leader. After thirty years, her husband retired and the couple moved to Florida. When her husband passed away, McMahon moved to High Point, North Carolina, where she lives with her oldest son. She had three sons, a daughter, and six grandchildren.