Robert Clark, Jr. was a Lieutenant and Quartermaster (appointed in 1833 by Lewis Cass) in the 11th Regiment, Michigan Militia. He was a Deputy U.S. Land Surveyor, and as such, surveyed in the Grand Rapids and St. Joseph County, Michigan, areas. In 1828-1829 he moved to and bought land in the White Pigeon Village, Michigan, area which he had surveyed with other surveyors. He surveyed, mapped, and platted White Pigeon on May 6, 1830 with other interested parties. Also, he surveyed the territorial road from Nottawa Township (St. Joseph County, Michigan) to Grand Rapids in 1833. He was paid six dollars for 15 miles of surveying.
Clark married Mary E. Clark (died circa 1867.) They had two sons, one of whom was John Marshall Clark, born in 1837, whose Papers are also in the Clarke. Robert Clark died in 1837. In 1849 Mary and their sons moved to Chicago, purchasing a dairy farm near the city on Clark Street, which made them immensely wealthy. (Some of this information is from the History of St. Joseph County, Michigan.)