There are 9 US Post Offices in Porter County serving a total of 157,705 residents equating to 17,523 residents per post office. It's estimated that approximately 251,715 packages are handled across the 9 county post offices annually. Porter County is a county located in the U.S. state of Indiana. As of 2010, the population was 164,343. The county seat is Valparaiso. This county is part of Northwest Indiana as well as the Chicago metropolitan area. Porter County is the site of the Indiana Dunes, an area of ecological significance. A museum called the Hour Glass located in Ogden Dunes, contains exhibits that document the ecological significance."