Belknap is a village located in Johnson County, Illinois. Belknap has a 2026 population of 86. Belknap is currently declining at a rate of 0% annually and its population has decreased by 0% since the most recent census, which recorded a population of 86 in 2020.
The median household income in Belknap is $67,500 with a poverty rate of 6.09%. The median age in Belknap is 50.5 years: 50.7 years for males, and 45.6 years for females. For every 100 females there are 101.8 males.