Saint Charles is a city in, and the county seat of, St. Charles County, Missouri. The population is about 70,000, making St. Charles the ninth-largest city in Missouri. It is located along the Missouri River, and is a northwestern suburb of St. Louis.

Prostitution and sex trafficking activity in St. Charles County have been well-documented for decades. Among the tactics used to address these and related crimes are those focused on reducing consumer-level demand and holding sex buyers accountable. For example, in June 2017, fourteen people were arrested during a web-based reverse sting operation conducted by the St. Louis County Police Multijurisdictional Human Trafficking Task Force and collaborating agencies. The target was consumer level demand, specifically those seeking to purchase sex from potential human trafficking victims. The investigation concluded with 14 people alleged to have tried to purchase sex from potential trafficking victims between June 19, 2017, and June 22, 2017, at various locations within St. Louis County and St. Charles County. The names, ages, and addresses of the 14 individuals were listed in news reports. Thirteen of those arrested were from the St. Louis area, one was from Michigan.

In November, 2022, the St. Charles Police Department conducted an undercover sex trafficking sting, resulting in 11 individuals being charged. During the operation, undercover police officers were contacted by individuals seeking a sexual encounter in exchange for money. Once contact was made with the suspect, they were taken into custody by police. The St. Charles County Prosecuting Attorney’s Office publicly disclosed the identities of the arrested men, who had each been charged with one count of patronizing prostitution.