Elected by the state legislature in a joint convention.
Ramsey was a former Whig U.S. Representative from Pennsylvania (CD 14, 1843-1847), Minnesota Territorial Governor (1849-1853), and Mayor of St. Paul (1855), and sitting Governor. Ramsey's main challengers for the Republican nomination were Cyrus Aldrich, David Cooper, and James Smith during balloting on January 12, 1863.
Chatfield was a former New York state legislator and Associate Justice of the Minnesota Territorial Supreme Court (1853-1858).