Born in Indiana county, Pennsylvania, in April, 1845, and came to Benton county in 1857, with the rest of the family. He is a son of Hugh and Margaret (Mack) St. Clair. He lived in his native state until ten or eleven years of age, and remained on his father's farm except when away at school, until about ten years since. He went to college at Iowa City, although he did not graduate, and then read law in the office of Shane & McCartney; he was admitted to the bar of Iowa, in October, 1867, but his poor health forbade the practice of law soon after, so he returned to the farm in 1869, remaining there until January, 1899. He then went into mercantile business in Mount Auburn, under the name of St. Clair & St. Clair. Mr. St. Clair has a natural gift for business, and has prospered well, considering the fact that much of the time he has been in poor health. He was a successful farmer, and now owns a quarter section in Cedar township. He is a member of the United Presbyterian church, and politically is a Republican. Mr. St. Clair has the entire confidence and esteem of his fellow citizens, who have elected him to fill several township offices, and he represented Benton county in the nineteenth assembly of the state legislature. December 22, 1877, Mr. St. Clair married Sarah, daughter of John and Mary White, who came from Ireland to Ohio, and later to Iowa.