 From 1870 to 1871 he worked as Assistant Geologist with the Ohio State Geological Survey.Between 1870 and 1872 he occupied the post of Assistant Chemist at the United States Department of Agriculture.Hired by the Japanese government on a three-year contract from 1872 and 1875, Munroe was assigned to Yesso (now Hokkaidō), in northern Japan, as Assistant Geologist and Mining Engineer with the Geological Survey of Yesso for the Hokkaidō Colonization Agency.