The 2014 Harrisburg, Illinois, population is 8,962. There are 1,368 people per square mile (population density).
The median age is 36.9. The US median is 37.2. 48.92% of people in Harrisburg, Illinois, are married. 13.13% are divorced.
The average household size is 2.3 people. 25.40% of people are married, with children. 22.37% have children, but are single.
89.19% of people are white, 6.84% are black, 1.08% are asian, 0.99% are native american, and 0.09% claim 'Other'.
2.46% of the people in Harrisburg, Illinois, claim hispanic ethnicity (meaning 97.55% are non-hispanic).