Question: Gary/Chicago International Airport is located in which county ?
Context: Air Wisconsin Airlines is a regional airline based at Appleton International Airport in the town of Greenville, Wisconsin, United States, near Appleton.  Air Wisconsin is the largest privately held regional airline in the United States.  It currently operates regional jet flights as American Eagle under contract to American Airlines via a code sharing agreement, serving cities in the U.S. and Canada with hubs at Boston Logan International Airport (BOS), Charlotte Douglas International Airport (CLT), Philadelphia International Airport (PHL) and Ronald Reagan Washington National Airport (DCA) .  Air Wisconsin previously operated United Express service on behalf of United Airlines followed by US Airways Express service on behalf of US Airways prior to becoming an American Eagle regional air carrier.  The company has announced it will once again partner with United Airlines as a United Express code sharing air carrier with primary hubs to be located at Chicago O'Hare International Airport (ORD) and Washington Dulles International Airport (IAD) beginning in September 2017 and will be "exclusively operating" as United Express by March 2018. Gary/Chicago International Airport (IATA: GYY, ICAO: KGYY, FAA LID: GYY) is a joint civil-military public airport in Gary, in Lake County, Indiana, United States.  It is three miles northwest of the city center and 25 miles (40 km) southeast of the Chicago Loop.  It is operated by the Gary/Chicago International Airport Authority, the basis for which was formed by the Chicago Gary Airport Compact signed in 1995.  Nearby highway connections include I-90, I-80, I-94, I-65 and the Chicago Skyway. DuPage Airport (IATA: DPA, ICAO: KDPA, FAA LID: DPA) is a general aviation airport located 29 mi west of downtown Chicago in West Chicago, DuPage County, Illinois.  It is owned and operated by the DuPage Airport Authority, which is an independent government body established by law by the State of Illinois.  It also serves as a reliever airport for O'Hare International Airport and Chicago Midway International Airport, both in nearby Chicago. Northern California TRACON (NCT) (Terminal Radar Approach Control), or NorCal TRACON for short, is an air traffic control facility that provides safety alerts, separation, and sequencing of air traffic arriving, departing, and transiting the airspace and airports in Northern California.  Located in Rancho Cordova near Sacramento, NCT controls airspace over 19000 square miles, and serves Reno International Airport, Sacramento International Airport, San Jose International Airport, Oakland International Airport, and San Francisco International Airport, plus 19 other smaller airports with air traffic control towers.  NCT is the 3rd busiest TRACON in America.  NorCal TRACON is the step between local control (in an airport's control tower) and Air Route Traffic Control Center (ARTCC), in this case, Oakland Center (ICAO code: ZOA).  San Francisco International Airport is the 2nd largest airport in California and the largest airport serving Northern California. Gary Airport/Clark Road is a South Shore Line commuter station serving the city of Gary, Indiana.  The station is located in the city's Brunswick neighborhood.  It is one of three NICTD electric train stations in Gary, and serves the Gary/Chicago International Airport, although it does not provide direct access to the airport.  NICTD gives the address as being on Clark Road near 2nd Avenue, approximately 1 mi from Airport terminal, but it is actually on the corner of 2nd Place, one block south of its supposed location.  Gary International Airport gives the station as being 1.5 mi from the airport terminal.  Clark Road has the lowest ridership on the entire South Shore Line. Chicago Rockford International Airport (IATA: RFD, ICAO: KRFD, FAA LID: RFD) , is an international airport located in Winnebago County, Illinois.  It is located four miles (6 km) south of the city center of Rockford and 85 miles northwest of Chicago.  Established in 1946, Chicago-Rockford International Airport is the busiest airport in Northern Illinois (with the exception of Chicago O'Hare and Chicago Midway).  In 2016, the airport served nearly 102,000 passengers. SkyValue, formally known as SkyValue USA, was a seasonal American low-cost airline that was headquartered in Fort Lauderdale, Florida, and for the 2006–07 winter season, its only season of operations, operated from a hub at Gary/Chicago International Airport (GYY) in Gary, Indiana, which lies 25 miles southeast of the Chicago Loop. A major airport has been proposed to be built in Peotone, Illinois, a suburb of Chicago.  There is no official name and two separate plans exist, one known as the "South Suburban Airport" and another known as "Abraham Lincoln National Airport".  The FAA refers to the two proposals as South Suburban Airport.  The airport would serve as an additional airport in the Chicago metropolitan area.  Supporters of the airport say it will bring new jobs to the southern suburbs and the entire Chicago region, while relieving critical runway and terminal congestion at O'Hare International Airport and Chicago Midway International Airport.  A new airport would accommodate large jet service similar to that of O'Hare, but that Midway International Airport does not offer. Gary ( ) is a city in Lake County, Indiana, United States, 25 mi from downtown Chicago, Illinois. Chicago O'Hare International Airport (IATA: ORD, ICAO: KORD, FAA LID: ORD) , also known as O'Hare Airport, Chicago International Airport, Chicago O'Hare, or simply O'Hare ( ), is an international airport located on the Far Northwest Side of Chicago, Illinois, 17 mi northwest of the Loop.  It is the primary airport serving the Chicago metropolitan area, with Midway International Airport, which is about 10 mi closer to the Loop and serves as a secondary airport.  It is operated by the City of Chicago Department of Aviation.
Answer: Lake County