As of the census of 2000, there were 80,098 people, 31,388 households, and 15,725 families residing in the city. The population density was 2,849.4 people per square mile (1,100.2/km²). There were 32,761 housing units at an average density of 1,165.4/sq mi (450.0/km²). The racial makeup of the city was 83.80% White, 5.09% African American, 2.93% Native American, 3.78% Asian, 0.07% Pacific Islander, 1.36% from other races, and 2.97% from two or more races. Hispanic or Latino of any race were 3.65% of the population. 23.8% were of German, 10.6% English, 10.1% Irish and 7.1% American ancestry according to Census 2000. 91.0% spoke English, 2.9% Spanish and 1.0% Chinese or Mandarin as their first language.
Of the 31,388 households, 25.1% included children under the age of 18, 38.0% were married couples living together, 8.7% had a female householder with no husband present, and 49.9% were non-families. 30.6% of all households were made up of individuals and 5.6% 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 2.93.
In the city the population was spread out with 18.6% under the age of 18, 30.7% from 18 to 24, 28.5% from 25 to 44, 15.1% from 45 to 64, and 7.2% who were 65 years of age or older. The median age was 25 years. For every 100 females there were 98.8 males. For every 100 females age 18 and over, there were 98.2 males.
The median income for a household in the city was $34,669, and the median income for a family was $51,545. Males had a median income of $33,481 versus $27,436 for females. The per capita income for the city was $19,378. About 7.3% of families and 18.9% of the population were below the poverty line, including 10.6% of those under age 18 and 7.7% of those age 65 or over.
Passenger train service is provided by Amtrak at the Lawrence Amtrak station.
Two bus systems operate in the city; "The T" is a public bus system operated by the city and "KU On Wheels" is operated by the University of Kansas. As of fall 2008, both bus systems are free to KU students.