| County: | Stephenson County |
| State: | Illinois |
| Ex Image: | Stephenson County Courthouse.jpg |
| Ex Image Cap: | Stephenson County Courthouse |
| Founded: | 1837 |
| Named For: | Benjamin Stephenson |
| Seat Wl: | Freeport |
| Largest City: | Freeport |
| Area Total Sq Mi: | 565 |
| Area Land Sq Mi: | 565 |
| Area Water Sq Mi: | 0.5 |
| Area Percentage: | 0.09 |
| Population As Of: | 2020 |
| Population Total: | 44630 |
| Pop Est As Of: | 2023 |
| Population Est: | 43105 |
| Population Density Sq Mi: | auto |
| Time Zone: | Central |
| Web: | www.co.stephenson.il.us |
| District: | 16th |
| District2: | 17th |
Stephenson County is a county located in the U.S. state of Illinois. According to the 2020 United States Census, it had a population of 44,630.[1] Its county seat is Freeport.[2] Stephenson County is included in the Freeport, IL Micropolitan Statistical Area, which is also included in the Rockford-Freeport-Rochelle, IL Combined Statistical Area.
The land that became Stephenson County was first settled by William Waddams in 1832, who founded Waddams Grove.[3] By 1837, population was sufficient to form Stephenson County, taking land from Jo Daviess and Winnebago counties. The county was named for Colonel Benjamin Stephenson, an official of the Illinois Territory.[4]
According to the US Census Bureau, the county has a total area of, of which is land and (0.09%) is water.
In recent years the average temperatures in the county seat of Freeport, have ranged from a low of in January to a high of in July, although a record low of was recorded in January 2009 and a record high of was recorded in July 1988. Average monthly precipitation ranged from in January to in June.
As of the 2010 United States Census, there were 47,711 people, 19,845 households, and 13,015 families residing in the county.[5] The population density was . There were 22,081 housing units at an average density of .[6] The racial makeup of the county was 86.5% white, 9.0% black or African American, 0.6% Asian, 0.2% American Indian, 1.2% from other races, and 2.5% from two or more races. Those of Hispanic or Latino origin made up 2.9% of the population.[5] In terms of ancestry, 46.6% were German, 12.5% were Irish, 10.0% were English, and 8.0% were American.[7]
Of the 19,845 households, 28.6% had children under the age of 18 living with them, 50.3% were married couples living together, 11.2% had a female householder with no husband present, 34.4% were non-families, and 29.7% of all households were made up of individuals. The average household size was 2.36 and the average family size was 2.90. The median age was 43.1 years.[5]
The median income for a household in the county was $43,304 and the median income for a family was $54,224. Males had a median income of $41,672 versus $29,510 for females. The per capita income for the county was $22,608. About 12.3% of families and 14.8% of the population were below the poverty line, including 24.1% of those under age 18 and 7.3% of those age 65 or over.[8]
There are five public high schools and one private high Schools in the county: (approximate enrollment included)
Public high schools
Private high school