Boulder is located in Illinois. Boulder, Illinois has a population of1,631.
The median household income in Boulder, Illinois is $58,661. The median household income for the surrounding county is $68,873 compared to the national median of $66,222. The median age of people living in Boulder is 40.8 years.
The average high temperature in July is 87.7 degrees, with an average low temperature in January of 18.8 degrees. The annual precipitation is 40.64.