Grafton is the oldest city in Jersey County, Illinois, United States. It is located near the confluence of the Illinois and Mississippi Rivers. As of the 2010 U.S. census, the city had a total population of 674. Prior to the Great Flood of 1993, Grafton had enjoyed a stable population of nearly 1,000 residents.
Grafton is located at 38°58′16″N 90°26′13″W / 38.97111°N 90.43694°W / 38.97111; -90.43694 (38.971115, -90.436818).
According to the 2010 census, Grafton has a total area of 3.7 square miles (9.58 km), all land.
As of the census of 2000, there were 609 people, 265 households, and 174 families residing in the city. The population density was 150.2 people per square mile (57.9/km²). There were 293 housing units at an average density of 72.2 per square mile (27.9/km²). The racial makeup of the city was 99.01% White, 0.16% African American, 0.16% Native American, and 0.66% from two or more races. Hispanic or Latino of any race were 0.99% of the population.
There were 265 households out of which 23.0% had children under the age of 18 living with them, 51.7% were married couples living together, 10.6% had a female householder with no husband present, and 34.0% were non-families. 29.1% of all households were made up of individuals and 15.1% had someone living alone who was 65 years of age or older. The average household size was 2.30 and the average family size was 2.84.
In the city, the population was spread out with 20.0% under the age of 18, 8.4% from 18 to 24, 23.3% from 25 to 44, 31.2% from 45 to 64, and 17.1% who were 65 years of age or older. The median age was 44 years. For every 100 females, there were 93.3 males. For every 100 females age 18 and over, there were 99.6 males.
The median income for a household in the city was $34,706, and the median income for a family was $44,250. Males had a median income of $35,000 versus $22,250 for females. The per capita income for the city was $21,989. About 9.4% of families and 14.0% of the population were below the poverty line, including 33.3% of those under age 18 and 10.6% of those age 65 or over.