Williams Township is a township in Northampton County, Pennsylvania, United States. The township's population was 6,581 at the 2020 census. The township is part of the Lehigh Valley metropolitan area, which had a population of 861,899 and was the 68th-most populous metropolitan area in the U.S. as of the 2020 census.

Interstate 78 (I-78) is a major east–west Interstate Highway stretching from Union Township, Lebanon County, Pennsylvania, in the west to the Holland Tunnel and New York City in the east. In Pennsylvania, I-78 runs for about 78 miles (126 km) from the western terminus at I-81 in Union Township east to the New Jersey state line near Easton in Northampton County.