Crystal Lake is a city in McHenry County, Illinois, United States. Named after a lake 1.6 miles (2.6 km) southwest of the city's downtown, Crystal Lake is 45 miles (72 km) northwest of Chicago. The population was 40,269 as of the 2020 census. Crystal Lake is the most populous city in McHenry County, part of the Chicago metropolitan area.

The Salvation Army (TSA) is a Protestant Christian church and an international charitable organization headquartered in London, England. It is aligned with the Wesleyan-Holiness movement. The organization reports a worldwide membership of over 1.7 million, consisting of soldiers, officers, and adherents who are collectively known as salvationists. Its founders sought to bring salvation to the poor, destitute, and hungry by meeting both their "physical and spiritual needs". It is present in 133 countries, running charity shops, operating shelters for the homeless, and disaster relief and humanitarian aid to developing countries.