As of the census of 2000, there were 90,352 people, 34,411 households, and 22,539 families residing in the city.
The population density was 3,795.1 people per square mile (1,465.1/km²). There were 36,004 housing units at an average density of 1,512.3/sq mi (583.8/km²). The racial makeup of the city was 83.64% White, 7.68% African American, 0.44% Native American, 0.99% Asian, 0.04% Pacific Islander, 4.83% from other races and 2.38% from two or more races. 9.96% of the population were Hispanic or Latino of any race. 25.5% were of German, 11.5% Italian, 7.1% Irish and 6.6% Polish ancestry according to Census 2000.
There were 34,411 households out of which 34.1% had children under the age of 18 living with them: 47.1% were married couples living together, 13.9% had a female householder with no husband present and 34.5% were non-families. 28.4% of all households were made up of individuals and 10.3% had someone living alone who is 65 years of age or older. The average household size was 2.54 and the average family size was 3.13.
In the city the population included 27.2% under the age of 18, 10.1% from 18 to 24, 31.5% from 25 to 44, 19.0% from 45 to 64, and 12.2% who were 65 years of age or older. The median age was 34 years. For every 100 females there were 96.7 males. For every 100 females age 18 and over, there were 93.2 males.
On October 10, 2008, the Wisconsin Department of Administration reported that Kenosha's population had grown by 6.2 percent since the 2000 census, and Kenosha County's population grew by 8.4 percent, a gain of 12,517 within that same period.
Kenosha has been served by rail service to and from Chicago since May 19, 1855, when the predecessors to the Chicago and North Western Railway, the Milwaukee and Chicago Railway Company (originally the Illinois Parallel Railroad) and the original Lake Shore Railroad (later the Green Bay, Milwaukee and Chicago Railway) were officially joined with great ceremony just south of today's 52nd Street. Passenger service began on May 28, 1866 and continues to the present day.
Kenosha has the only Metra station in Wisconsin, with nine inbound and nine outbound trains each weekday. Not all Union Pacific/North Line trains terminate and originate in Kenosha; most terminate at Waukegan, Illinois to the south. Plans are underway to extend Regional Transportation Authority passenger service northwards from the Kenosha Metra Station through Racine County and into Milwaukee via the proposed KRM Line.
Since June 2000, a two-mile streetcar route has served the downtown area and HarborPark, connecting the Metra station with downtown and several area parks. Kenosha is one of the smallest cities in America with any type of streetcar system today. In December 2005 the city council authorized a study on the expansion of streetcar service in order to connect the city's downtown with the uptown business districts flanking 63rd Street and 22nd Avenue.
Kenosha was the first city to color-code transit routes (with the Blue, Green, Red and Orange Lines) and the first city to use electric trolley buses in full transit service, both occurring on February 14, 1932.
Kenosha is served by Interstate 94 between Chicago and Milwaukee, and by Amtrak's Hiawatha Line service (via the Sturtevant station in Racine County) between Chicago and Milwaukee, which runs seven times daily.
In Kenosha, numbered streets run east-west and numbered avenues north-south, with street numbering commencing with First Street on Kenosha County's northern border (County Trunk Highway KR) rather than at the city's center. ('Roads' are diagonal thoroughfares, 'Courts' are short north-south avenues, and 'Places' are short east-west streets.) The downtown area is between 50th and 60th Streets. Avenue numbers increase as one heads west from the lake front. This numbering system continues through all of Kenosha County, ending at 408th Avenue to the west at the Kenosha-Walworth County line, while north-south roads end at the Illinois state line at 128th Street. (Edmonton, Alberta has a similar numbering system.)