The suit, filed Thursday in federal court, also asks that the company -- based in San Francisco -- reimburse Cook County more than $100,000 to cover the cost of wages for officers who work on prostitution and human trafficking through the Web site, the Chicago Sun-Times reported Thursday.
"We're asking them to do what frankly they should have been doing all along -- stop facilitating prostitution," Dart said. "Stop being the largest source of prostitution in America."
Sheriff's police have arrested 200 people on a variety of prostitution-related charges since January 2007 that officials said were directly linked to ads posted on Craigslist.
Craiglist Chief Executive Officer Jim Buckmaster issued a statement saying "misuse of Craigslist to facilitate criminal activity is unacceptable."
"Misuse of the site is exceptionally rare compared to how much the site is used for legal purposes," Buckmaster said. "Craigslist is an extremely unwise choice for those intent on committing crimes, since criminals inevitably leave an electronic trail to themselves that law enforcement officers will follow."
Buckmaster said the company assists police across the nation "on a daily basis."
However, Dart says Craigslist provides pimps with a way to "insulate" themselves from ilegal transactions and he called the company "an accomplice" to prostitution.