Oscoda County was established March 10, 1881. Previously, it had been Comins Township attached to Alcona County, which had been formed about 1869 when it was split from Alpena County. Prior to that, the area belonged to the Indians who ceded it to the United States Government by the Treaty of Saginaw in 1819.

As originally constituted, Oscoda County consisted of three townships: Atherton, Mt. Pindus, and Comins. Since then, there have been as many as nine townships, as the population ebbed and flowed with the lumbering & railroad industries.

There are currently no incorporated cities or villages in the county, including Mio, the county seat. The present courthouse was built in 1888 at a cost of $3,754, including woodshed and out-houses, which (thankfully) have long since disappeared.

Incredibly, a public water system existed between 1890 and 1910. The water was pumped from Wolf Creek by two hydrolic rams through a 4" wooden pipe to a reservoir on the hill south of town. A six inch wooden main, with which the customers were connected by means of east-west branches, ran from the reservoir down M-33 as far as M-72.

The Act of 1881 which established the county, also designated Union Corners, in the southwest corner of the county, as temporary county seat and directed an election to choose a permanent location. After a couple of attempts, Mio was selected because of its central location. Even after that, several efforts were made to move the county seat to a different site, but with the erection of the courthouse in 1888, discussion ended.

How Mio got its name is not well documented. In 1881, the local newspaper spelled it Mioe. This was the family's name for Marla Deyarmond, an early settler. A visit to her house was termed "going to Aunt Mioe's". There being little else there at the time, Aunt Mioe's became synonymous with the settlement.

At one time, Fairview was located a mile and a half north of its present site; at another, it was a mile north and a mile east of where it is now. Since there wasn't much else to it, the town was wherever the postoffice was located.

Luzerne, settled during the early lumber days, never had a railroad, but it did have a sawmill and gristmill powered by a dam on Big Creek. This dam also stored water for running logs down Big Creek to the AuSable River. Luzerne's zenith was reached during the 1890's when for some years it was the site of an annual agricultural fair. The fair was held on the flat land at the northwest corner of present M-72 and County Highway 489.

In the early days, McKinley - then known as Pott's Headquarters - was the hub of the county's lumbering industry. From there, narrow gauge railroads ran north and west for many miles. Most of the rails and rolling stock for this network was floated down the AuSable on rafts from Grayling. Even though McKinley grew to be the largest settlement in the county, with churches, stores, hotels, and other businesses, it remained somewhat isolated from larger settlements on Michigan's east coast. The only way to ship anything to or from Lake Huron was by river or ox team.

Sometime in the 1890's a narrow gauge railroad was put through from AuSable, on the coast of Lake Huron, to Comins, a settlement in what is now Clinton Township. The presence of the railroad quickly established Comins as the new center of commerce for Oscoda County. Around it sprang up a bank, a hotel, a jail, stores, saloons, stockyards, a roundhouse, a water tank, and many dwellings. About 1912, the railroad was widened to standard gauge and connected with the Detroit & Mackinaw Railroad. Livestock and other products of the area were hauled or driven for shipment, and supplies were shipped in for distribution by team or truck to Mio and other parts of the surrounding country. As time went by, however, the railroad slowly lost its importance and became unprofitable. In 1928, the last train chugged off down the tracks taking with it Comins' importance as a shipping center.