Dunn secured the school's original financial support by riding on horseback for thousands of miles through the frontier lands of Michigan, Minnesota, and Wisconsin in the early 1850s, gathering donations. In Minneapolis in 1882, at the 25th General Conference of the Free-will Baptist Church, Dunn was chosen to be the moderator. In 1838, he met a relative of Ethan Allen, Mary Eliza Allen (died 1848), and they married in Ohio soon thereafter. They had three children. Sons Newell Ransom Dunn (1841–1863) and Francis Wayland Dunn (Wayne, Ohio 1843–1874) both served in the Civil War. The youngest was a daughter, Cedelia Dunn (1845–1858). In September 1849, he married Cyrena A. Emery (1824–1896) in Dover, New Hampshire; and they lived in Boston. They had at least three children, daughters, S. Abbie Dunn Slayton, Helen ("Nellie") Dunn Gates, and Nettie Dunn. Daughter Helen was the author of "A consecrated life, a sketch of the life and labors of Rev. Ransom Dunn, D. D., 1818–1900". Dunn died in 1900 in Scranton, Pennsylvania. He is buried with his wife, Cyrena, at Oak Grove Cemetery, Hillsdale, Michigan.