Osseo is a city located in Trempealeau County, Wisconsin, at the confluence of the North and South Forks of the Buffalo River. As of the 2000 census, the city had a total population of 1,669.
Osseo is located at 44°34'42" North, 91°13'6" West (44.578306, -91.218273).
According to the United States Census Bureau, the city has a total area of 2.1 square miles (5.4 km²), of which, 2.1 square miles (5.3 km²) of it is land and 0.04 square miles (0.1 km²) of it is water. The total area is 0.96% water.