Unionville has been the judicial seat of Putnam County since 1853 and stands 1070 feet above sea level in a region of wooded hills, rolling prairies, and glacial plains in north Missouri. First named Harmony, it became the fifth designated county seat as officials sought a central location while county boundaries changed. Putnam County, named for Revolutionary War Gen. Israel Putnam, was organized in 1845 with a large area, then reduced in 1846 by the creation of Dodge County; both counties extended nine miles into Iowa until the U.S. Supreme Court established the Missouri-Iowa boundary in 1851, and Dodge County was reabsorbed by Putnam in 1853. Unionville and Putnam County were pro-Union during the Civil War and saw little action, but growth stopped until progress returned with the arrival of the Burlington and Southwestern Railroad, later the C.B. and Q., in 1873 and with the development of coal mining in the 1880s. The Putnam dye industry, later based in Quincy, Illinois, began in Unionville in 1891 as Monroe Drug Co., founded by E. N. Monroe, J. H. Elson, and others, and the first Missouri chapter of the P.E.O. was organized there in 1886. Unionville became the marketing, banking, and legal center of a livestock farming and coal mining county where Sac, Fox, and Iowa tribes continued to roam into the 1840s after giving up claims in 1824. Brightwell Martin is said to have been the county's first permanent white settler in the winter of 1836. Coal mining in the county began in 1879, and Mendota was founded in 1881 by the Mendota Coal and Mining Co. Nearby were earlier county seat sites at Putnamville, Calhoun, Winchester, and Fairplay, while St. John to the northwest served as the seat of the short-lived Dodge County. Mormons are said to have passed through part of the county in 1846 and rested at the St. John city well. Putnam County was also home to Henry Clay Dean, a lecturer, lawyer, and writer whose home, Rebel Cove on the Chariton River, was once a showplace before it burned, and to John C. McKinley, born near Mendota, who served as Missouri's lieutenant governor from 1905 to 1909.