Lawrence County is the easternmost county in the U.S. state of Illinois (excluding water boundaries). According to the 2010 census, it has a population of 16,833. Its county seat is Lawrenceville.
According to the U.S. Census Bureau, the county has a total area of 374 square miles (970 km), of which 372 square miles (960 km) is land and 2.0 square miles (5.2 km) (0.5%) is water.
As of the 2010 United States Census, there were 16,833 people, 6,130 households, and 4,056 families residing in the county. The population density was 45.2 inhabitants per square mile (17.5/km). There were 6,936 housing units at an average density of 18.6 per square mile (7.2/km). The racial makeup of the county was 87.3% white, 9.6% black or African American, 0.2% Asian, 0.2% American Indian, 1.7% from other races, and 1.0% from two or more races. Those of Hispanic or Latino origin made up 3.3% of the population. In terms of ancestry, 12.7% were German, 10.4% were American, 9.5% were Irish, and 7.8% were English.
Of the 6,130 households, 28.6% had children under the age of 18 living with them, 50.7% were married couples living together, 10.7% had a female householder with no husband present, 33.8% were non-families, and 30.1% of all households were made up of individuals. The average household size was 2.34 and the average family size was 2.88. The median age was 39.7 years.
The median income for a household in the county was $38,771 and the median income for a family was $45,565. Males had a median income of $40,949 versus $25,991 for females. The per capita income for the county was $19,297. About 14.8% of families and 17.5% of the population were below the poverty line, including 26.9% of those under age 18 and 7.7% of those age 65 or over.