Abingdon is a city in Knox County, Illinois, 50 miles (80 km) west of Peoria. It is part of the Galesburg Micropolitan Statistical Area. The city was first settled in 1828 and was incorporated in 1857. In 1894, the patent for the common spring-loaded mousetrap was given to William Hooker of Abingdon, Illinois. In 1890, 1,321 people lived here; in 1900, 2,022; and in 1910, 2,464. The population was 3,612 at the 2000 census.
Abingdon is located at 40°48′13″N 90°24′3″W (40.803572, -90.400770).
According to the 2010 census, the city has a total area of 1.46 square miles (3.8 km2), all land.
As of the census of 2000, there were 3,612 people, 1,422 households, and 984 families residing in the city. The population density was 2,475.1 people per square mile (955.2/km²). There were 1,535 housing units at an average density of 1,051.9 per square mile (405.9/km²). The racial makeup of the city was 98.12% White, 0.55% African American, 0.25% Native American, 0.11% Asian, 0.17% from other races, and 0.80% from two or more races. Hispanic or Latino of any race were 1.14% of the population.
There were 1,422 households out of which 31.8% had children under the age of 18 living with them, 54.1% were married couples living together, 10.8% had a female householder with no husband present, and 30.8% were non-families. 26.2% of all households were made up of individuals and 14.5% had someone living alone who was 65 years of age or older. The average household size was 2.50 and the average family size was 2.99.
In the city the population was spread out with 25.8% under the age of 18, 7.9% from 18 to 24, 27.7% from 25 to 44, 22.6% from 45 to 64, and 16.0% who were 65 years of age or older. The median age was 38 years. For every 100 females there were 90.2 males. For every 100 females age 18 and over, there were 87.3 males.
The median income for a household in the city was $35,642, and the median income for a family was $40,337. Males had a median income of $31,042 versus $20,343 for females. The per capita income for the city was $15,711. About 6.2% of families and 9.9% of the population were below the poverty line, including 11.1% of those under age 18 and 13.5% of those age 65 or over.