Montello is a city in and the county seat of Marquette County, Wisconsin, United States. The population was 1,397 at the 2000 census. The Fox River flows through the city. Montello is home to the largest tree in Wisconsin.
Montello is located at 43°47′31″N 89°19′47″W / 43.79194°N 89.32972°W / 43.79194; -89.32972 (43.791976, -89.329771).
According to the United States Census Bureau, the city has a total area of 2.2 square miles (5.6 km²), of which, 1.9 square miles (4.9 km²) of it is land and 0.2 square miles (0.6 km²) of it (11.63%) is water.