Westchester Township is one of twelve townships in Porter County, Indiana. It is included in the Calumet, Northwest Indiana, and Great Lakes regions. It is located on the southern shore of Lake Michigan, about 50 miles (80 km) southeast of Chicago. It stretches from the famous Indiana Dunes on its northern border, south to the Valparaiso Moraine, a ridge of rolling hills left by the last glacier to pass through the area. As of the 2010 census, its population was 19,396.

Porter County is a county in the U.S. state of Indiana. As of 2020, the population was 173,215, making it the 10th most populous county in Indiana. The county seat is Valparaiso. The county is part of Northwest Indiana, as well as the Chicago metropolitan area. Porter County is the site of much of the Indiana Dunes, an area of ecological significance. The Hour Glass Museum in Ogden Dunes documents the region's ecological significance.