The municipality of Bethlehem Township was formed in 1746 as a part of Bucks County. The name of Bethlehem itself originated from the German Moravian Brethren on Christmas Eve in 1741. The township, as originally defined, contained the current township as well as the townships of Upper Nazareth and Lower Nazareth. As shown on a page from the 1874 "Atlas of Northampton County", Upper and Lower Nazareth Townships had been created, but the then-borough of Bethlehem had not yet annexed the areas of Altona and parcels along Center Street (Bath Pike), Linden Street (Nazareth Pike), and Easton Avenue.