Dennison is located in Illinois. Dennison, Illinois has a population of 555. Dennison is more family-centric than the surrounding county with 53.95% of the households containing married families with children. The county average for households married with children is 30.62%.
The median household income in Dennison, Illinois is $90,963. The median household income for the surrounding county is $66,067 compared to the national median of $69,021. The median age of people living in Dennison is 37 years.
The average high temperature in July is 86.6 degrees, with an average low temperature in January of 19.8 degrees. The average rainfall is approximately 44.1 inches per year, with 18 inches of snow per year.