Indiana is a borough in and the county seat of Indiana County in the U.S. Commonwealth of Pennsylvania. The population was 13,975 at the 2010 census, and since 2013 has been part of the Pittsburgh metropolitan area after being a long time part of the Pittsburgh media market. Indiana is also the principal city of the Indiana, PA Micropolitan Statistical Area, and is also part of the larger Pittsburgh-New Castle-Weirton, PA-OH-WV Combined Statistical Area.