as of the 2010 united states census, there were 2,695,598 people and 1,194,337 households residing within the city limits of chicago. more than half the population of the state of illinois lives in the chicago metropolitan area. the 2000 united states census had shown the population density of the city itself was 12,750.3 people per square mile (4,923.0/km²), making it one of the nation's most densely populated cities. there were 1,152,868 housing units at an average density of 5,075.8 per square mile (1,959.8/km²). of the 1,061,928 households in the 2000 census, 28.9% had children under the age of 18 living with them, 35.1% were married couples living together, 18.9% had a female householder with no husband present, and 40.4% were non-families. the median income for a household in the city was $38,625 in 2000, and the median income for a family was $46,748. males had a median income of $35,907 versus $30,536 for females. below the poverty line were 19.6% of the population and 16.6% of the families.