National Weather Service Chicago currently known as National Weather Service Romeoville is a weather forecast office responsible for monitoring weather conditions for 23 counties in Northern Illinois, the Chicago metropolitan area and Northwest Indiana.[1] The Army Signal Service established the first federal weather office in the region in Chicago on October 15, 1870.[2] During May 1894 the Chicago Weather Bureau was given a new forecast area extending from the Great Lakes region all the way to the Rocky Mountains.[2] The current National Weather Service Chicago is located in Romeoville and is in charge of issuing local forecasts and weather warnings for the Chicago area.[2] It is one of only two National Weather Service offices in Illinois, the other being National Weather Service Central Illinois.