In 1804, McNair traveled to what is now Missouri, the United States having just acquired it following the
Louisiana Purchase. In that year, he married Marguerite Suzanne de Reihle de Regal, the daughter of a French marquis. He lived in
St. Louis, Missouri, participated in
Freemasonry as a member of
St. Louis Lodge 111, and served as a
United States Marshal. He also became a successful businessman, and served two terms on the Board of Trustees of the Town of St. Louis, in 1808 and 1813. On May 24, 1813,
Stephen F. Austin, who was later responsible for the colonization of
Texas, and for whom
Austin, Texas is named, was commissioned an ensign in the Missouri militia. Later in September, he enlisted as a private in the First Regiment of Mounted Militia commanded by Colonel Alexander McNair. McNair was elected governor in 1820, receiving 72% of the vote and defeating the famous explorer
William Clark. After his time as governor, he worked in the Indian Department until his death. ==Death==