At the 2000 census there were 93,759 people, 34,522 households, and 23,267 families in the county. The population density was 169 people per square mile. There were 43,783 housing units at an average density of 79 per square mile. The racial makeup of the county was 94.49% White, 0.84% Black or African American, 0.23% Native American, 0.65% Asian, 0.03% Pacific Islander, 2.62% from other races, and 1.14% from two or more races. 6.54% of the population were Hispanic or Latino of any race. Of the 34,522 households 31.80% had children under the age of 18 living with them, 55.40% were married couples living together, 8.20% had a female householder with no husband present, and 32.60% were non-families. 24.70% of households were one person and 9.20% were one person aged 65 or older. The average household size was 2.57 and the average family size was 3.07. The age distribution was 24.20% under the age of 18, 13.80% from 18 to 24, 27.60% from 25 to 44, 21.80% from 45 to 64, and 12.70% 65 or older. The median age was 35 years. For every 100 females there were 98.90 males. For every 100 females age 18 and over, there were 97.20 males. In 2017, there were 918 births, giving a general fertility rate of 48.8 births per 1000 women aged 15–44, the sixth lowest rate out of all 72 Wisconsin counties.
Owing to its Yankee heritage, which contrasts with the German-American or Scandinavian-American character of most of Wisconsin, Walworth County was initially a stronghold of the Free Soil Party. It voted for Martin van Buren and John P. Hale in Wisconsin's first two presidential elections, and its opposition to the spread of slavery meant it became rock-ribbed Republican in subsequent elections, even resisting the appeal of Wisconsin native Robert La Follette when he carried the state in 1924. Growth of conservative suburbs and resort towns has meant Walworth – unlike most historically free-soil Yankee counties – retains a decided Republican bent. The only Democrat to carry the county has been Woodrow Wilson in 1912, who won only 36 percent of the vote against a mortally divided GOP. Even then, Wilson only bested President William Howard Taft in the county by 29 votes. The best Democratic showings since then have been by Lyndon Johnson in 1964 and Barack Obama in 2008, both of whom received around 48 percent and narrowly lost the county while sweeping every antebellum free state. Franklin D. Roosevelt and Bill Clinton are the only other Democrats since Wilson to cross the 40 percent mark.
