Peoria is one of the oldest settlements in Illinois, much older than Chicago, as explorers first ventured up the Illinois River from the Mississippi. The lands that eventually would become Peoria were first settled in 1680, when French explorers René-Robert Cavelier, Sieur de La Salle and Henri de Tonti constructed Fort Crevecoeur. This fort would later burn to the ground, and in 1813 Fort Clark, Illinois was built. When the County of Peoria was organized in 1825, Fort Clark was officially named Peoria.
As of the census of 2000, there were 112,936 people, 45,199 households, and 27,345 families residing in the city. The population density was 2,543.4 people per square mile (982.1/km²). There were 49,125 housing units at an average density of 1,106.3/sq mi (427.2/km²). The racial makeup of the city was 69.29% White, 24.79% African American, 0.20% Native American, 2.33% Asian, 0.04% Pacific Islander, 1.20% from other races, and 2.16% from other races. Hispanic or Latino of any race were 2.51% of the population.