Coal City is a village in Grundy and Will counties in the U.S. state of Illinois.The population was 5,587 at the 2010 census.It is served by Interstate 55. confirmed EF3 tornado passed through Coal City during the outbreak of storms and tornadoes on Monday, June 22, 2015. The tornado touched down near Morris, Illinois, before entering Coal City damaging and destroying a number of homes and businesses.