Monticello is a city located in Piatt County Illinois. Monticello has a 2020 population of 5,856. It is also the county seat of Piatt County. Monticello is currently declining at a rate of -0.20% annually and its population has decreased by -0.76% since the most recent census, which recorded a population of 5,901 in 2010. Monticello reached it's highest population of 5,922 in 2016.
The average household income in Monticello is $78,623 with a poverty rate of 5.60%. The median rental costs in recent years comes to $970 per month, and the median house value is $158,300. The median age in Monticello is 41.6 years, 38.3 years for males, and 43.9 years for females.