Monroe County is bordered by Jackson County to the north, Juneau County to the east, Vernon County to the south, and La Crosse County to the west. Twenty-four townships make up the county, with the county seat located in Sparta. The 60,000-acre Fort McCoy Military Reservation is located in the north-central portion of the county and includes parts of six towns.
In 1848, the time when Wisconsin became a state, the area was inhabited by the Winnebago Tribe. However, other Native Americans may have lived or passed through the area before then. With the development of a state road between Prairie du Chien and Green Bay in 1849, settlers began coming to the area. The land was subsequently surveyed and immigrants flooded the area. The county was created by state legislation in 1854.
A logging and transportation boom in the 1850s led to the establishment of several lumber camps, mill sites, and railroad depots. These eventually grew into villages. Since the turn of the twentieth century, Monroe County has transitioned to an agriculture-based economy. The unique geography allows for agricultural uses from dairy farms to cranberry bogs.