Hosensack is an unincorporated community in Lower Milford Township in Lehigh County, Pennsylvania. It is part of the Lehigh Valley, which ha…Hosensack is an unincorporated community in Lower Milford Township in Lehigh County, Pennsylvania. It is part of the Lehigh Valley, which has a population of 861,899 and was the 68th most populous metropolitan area in the U.S. as of the 2020 census.