Ontario is a village in Vernon County, Wisconsin, United States. The population was 554 at the 2010 census. Ontario is located at 43°43′24″N 90°35′31″W / 43.72333°N 90.59194°W. According to the United States Census Bureau, the village has a total area of 1.01 square miles, of which, 1.00 square mile of it is land and 0.01 square miles is water.