The ongoing COVID-19 pandemic began in the U.S. state of Illinois on January 24, 2020, when a woman in Chicago, who had just returned from the pandemic's place of origin in Wuhan, Hubei, China, tested positive for the virus. This was the second case of COVID-19 in the United States during the pandemic. The woman's husband was diagnosed with the disease a few days later, the first known case of human-to-human transmission in the United States. Community transmission was not suspected until March 8, when a case with no connection to other cases or recent travel was confirmed.

The Cook County Jail, located on 96 acres in South Lawndale, Chicago, Illinois, is operated by the Sheriff of Cook County. It is sometimes referred to as California or Hotel California, as its address is on California Avenue. A city jail has existed on this site since after the Great Chicago Fire of 1871, but major County prisoners were not generally collocated here until closure of the old Hubbard Street Criminal Court Building and jail in 1929. Since then, a 1920s neoclassical and art deco courthouse for the criminal division of the Cook County Circuit Court has operated at the South Lawndale complex.