Fox River Grove (FRG) is a village in Algonquin Township, McHenry County and Cuba Township, Lake County, Illinois, United States. As per 2020 census, the population was 4,702. In 1919, the village of Fox River Grove was officially incorporated, becoming the ninth village in McHenry County. The Grove is situated along the southern shore of the Fox River.

McHenry County is a county located in the U.S. state of Illinois. According to the 2020 Census, it had a population of 310,229, making it the sixth-most populous county in Illinois. Its county seat is Woodstock. McHenry County is one of the five Illinois collar counties in the Chicago-Naperville-Elgin, IL-IN-WI Metropolitan Statistical Area. Long known as a center of recreation along with agriculture in the western portion, it has more recently experienced rapid rates of suburbanization, exurbanization and urbanization, but the western portions of the county remain primarily agricultural and rural.