[6] Before European colonization, several Native American tribes inhabited northeastern Ohio.

[7] After Europeans first crossed into the Americas, the land that became Medina County was colonized by the French, becoming part of the colony of Canada (New France).

Parts of Medina County and neighbouring Lorain became home to the Black River Colony founded in 1852, a religious community centered on the pious lifestyle of the German Baptist Brethren.

[9] As of the census of 2000, there were 151,095 people, 54,542 households, and 42,215 families living in the county.

26.8% were of German, 11.5% Irish, 8.6% Italian, 8.4% English, 8.4% Polish and 7.8% American ancestry according to Census 2000.

18.90% of all households were made up of individuals, and 6.90% had someone living alone who was 65 years of age or older.

As of the census of 2010, there were 172,332 people, 65,143 households, and 48,214 families living in the county.

[15] In terms of ancestry, 32.7% were German, 18.3% were Irish, 11.6% were English, 10.7% were Italian, 10.4% were Polish, and 7.4% were American.

Medina County is a Republican stronghold in presidential elections.