Monmouth is located in Illinois. Monmouth, Illinois has a population of 8,903. Monmouth is more family-centric than the surrounding county with 28% households with children. The county percentage for households with children is 25%.
The median household income in Monmouth, Illinois is $46,979. The median household income for the surrounding county is $53,274 compared to the national median of $66,222. The median age of people living in Monmouth is 34.7 years.
The average high temperature in July is 84.8 degrees, with an average low temperature in January of 14.8 degrees. The annual precipitation is 38.31.