Mio ( /maɪ.oʊ/) is an unincorporated community in the U.S. state of Michigan. It is the county seat of Oscoda County and is situated along the boundary between Mentor Township on the east and Big Creek Township on the west.
Mio is also a census-designated place (CDP) used for statistical purposes, but has no legal status as an incorporated municipality. As of the 2000 census, the CDP population was 2,016.
The town was founded in 1881, and was originally called “Mioe”, in honor of the wife of town founder, Henry Deyarmond. Other founders are Colige Comins, Reirlo Fosdick, and John Randall. A post office named Mioe opened May 3, 1882. The name changed to Mio on November 21, 1883. The Mio post office, with ZIP code 48647, also serves the northern portions of Mentor Township and the northeastern part of Big Creek Township, as well as a large area of eastern and southern Elmer Township and smaller portions of western Clinton Township and Comins Township.