Casnovia is a village in the U.S. state of Michigan. It is situated on the boundary between Muskegon County and Kent County and lies partially within both. As of the 2000 census, the village population was 315. The village is located partially within the Casnovia Township, Michigan.
Casnovia is believed to be the only place on Earth with that name, now or at any time in the past. The name is a distortion of the settlement's original name, Casanova Town, founded by Jedediah Craw in 1852. Craw was a Mormon with four wives, all teenagers at the time of his arrival in the area. The name Casanova Town was most likely bestowed on Craw's compound by neighbors, as a reference to his polygamous lifestyle. The settlement grew along what is now Ball Creek, and took the name Casnovia in 1861.
According to the United States Census Bureau, the village has a total area of 1.1 square miles (2.8 km²), all land.