Caro is a city in and the county seat of Tuscola County, Michigan, United States. The population was 4,328 at the 2020 census and 4,145 at the 2000 census.

The Thumb is a region and a peninsula of the U.S. state of Michigan, so named because the Lower Peninsula is shaped like a mitten. The Thumb area is generally considered to be in the Central Michigan region, east of the Tri-Cities and north of Metro Detroit. The region is also branded as the Blue Water Area.