Genesee County, named for the Genesee River Valley in western New York from which so many of its early settlers came, is located in the east central lower peninsula of Michigan. The name itself is derived from the Seneca word je-nish-hi-yeh, "beautiful valley". To the east are Lapeer and Oakland counties, to the west Saginaw and Shiawassee, to the north Saginaw and Tuscola, to the south, Oakland and Livingston. Genesee County was set off March 28, 1835, and formally organized March 8, 1836. Prior to that the territory within present Genesee County was part of Shiawassee, Saginaw and Lapeer Counties.

Genesee County, which occupies 655 square miles of land, has four rivers: the Flint, Thread, Yellow and Shiawassee. Of these, the important is the Flint River.

Although more than 50 miles from Detroit, Genesee County nevertheless had a population of 4,268 by 1840. The territory within the present Genesee County except for a small parcel of land in the northwest corner, was ceded to the United States by the treaty of 1807. The rest of Genesee was included in the 1819-20 Treaty of Saginaw.

The first township organized in Genesee County was Grand Blanc, which was established in March 9, 1833.

The first meeting of the board of Supervisors of Genesee County was held in the tailor shop of Daniel H. Seeley, over Stage and Wright's Store in Flint Township on October 4, 1836. Samuel Rice, representing Grand Blanc Lyman Stow, Flint, and Samuel W. Pattison, Argentine acting as the Board of Supervisors.

The first road to enter Genesee County was a trail cut from Saginaw to Flint by detachments of the Third United States infantry in the winter of 1822-1823. It was called the Saginaw Military Road though it was little more than a bridle path.

Today the Genesee County Road Commission maintains more than 1813 miles of Road and Streets and over 250 signalized intersections.