There are 26 US Post Offices in Lake County serving a total of 514,162 residents equating to 19,775 residents per post office. It's estimated that approximately 820,660 packages are handled across the 26 county post offices annually. Lake County is a county located in the U.S. state of Indiana. In 2010, its population was 496,005, making it Indiana's second-most populous county. The county seat is Crown Point. This county is part of Northwest Indiana and the Chicago metropolitan area, and contains a mix of urban, suburban and rural areas. It is the home to a portion of the Indiana Dunes and to Marktown, Clayton Mark's planned worker community in East Chicago."