Gary is a city in Lake County, Indiana, United States, 25 miles from downtown Chicago, Illinois.The population of Gary was 80,294 at the 2010 census, making it the ninth-largest city in the state of Indiana. From the middle of the twentieth century to the present, Gary has experienced drastic population loss, falling by 55 percent from its peak of 178,320 in 1960.Gary is adjacent to the Indiana Dunes National Lakeshore and borders Lake Michigan. The city is known for its large steel mills, and for being the birthplace of The Jackson 5 music group.