More than 300 "johns" were arrested in Cook County during a nationwide prostitution sting this summer. View Full Caption Getty

CHICAGO — A national prostitution sting has netted a record number of johns arrested for attempting to buy sex, and nowhere saw more johns arrested than Cook County.

That's according to the Cook County Sheriff's Office, which led a nationwide effort called the "national johns suppression initiative." The effort resulted in 1,300 "sex buyers" arrested across the country since July 1, the sheriff's office said.

Local police agencies arrested 230 sex buyers in Cook County, which was the most arrested in one area, according to the sheriff's office.

Seattle came in second for most johns arrested with 204, the sheriff said. Columbus came in third with 167 johns arrested.

The sheriff's office did not break down where the arrests were made in the county. A news release from the office said that 43 arrests in the county were done in partnership with a number of suburban police departments, including Lansing, Matteson and Broadview.

In one local case, a 15-year-old was arrested for attempting to buy sex, the sheriff's office said.

In Seattle, men participating in two separate bachelor parties were arrested for attempting to buy sex, the sheriff's office said. Police in Tennessee also rescued a 12-year-old girl who was abducted in Texas and trafficked to Tennessee, according to the sheriff.

Sheriff Tom Dart launched the nationwide effort targeting prostitution rings in 2011. This summer's sweep is the 12th operation from the task force, the sheriff said.

Since 2011, the task force has arrested 5,800 johns. Nearly a quarter of all johns arrested since 2011 were arrested this summer, according to data provided by the sheriff's office.

The sheriff's office said 60 percent of those arrested in the sting this year stemmed from online advertisements, and that 99 percent of them were posted on the site backpage.com, a classified ads site.

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