Monticello is a city in Jones County, Iowa, United States. As of the 2010 census, the city population was 3,796. It is part of the Cedar Rapids Metropolitan Statistical Area.
Monticello is located at 42°14′20″N 91°11′21″W / 42.23889°N 91.18917°W / 42.23889; -91.18917 (42.238759, -91.189067). According to the United States Census Bureau, the city has a total area of 3.7 square miles (9.6 km²), of which, 3.7 square miles (9.5 km²) of it is land and 0.04 square miles (0.1 km²) of it (0.54%) is water.
For many years, U.S. Highway 151 went directly through Monticello. In 2004, a four lane bypass around Monticello was completed and opened. As a result, the highway was moved about a mile south of the previous route.