[1] After the founding of Bethlehem, a number of settlements began to rise along the route, causing a constant use of it and the highway to be called King's Road.

[1] Bethlehem Pike and Germantown Avenue were the first two segments of the King's Highway, the main road carrying passengers and their goods between Philadelphia and the north.

During the American Revolutionary War, British officers gathered near the southern terminus of the modern day pike.

Further north along the route in the Whitemarsh Valley is the site where George Washington held Howe at bay, thus becoming famous in history as Church Hill.

[1] During the revolution, the pike dealt with a busy time period, for Bethlehem was crowded with officers, prisoners, and soldiers from the war.

Later, a letter had arrived by express courier from David Rittenhouse, announcing that all the military stores, in 700 wagons, were sent north on the Bethlehem Pike.

The road traverses Rockhill Township, where the New Jersey and Pennsylvania armies listened to Richard Peters in 1799, a member of the Colonial assembly.

[9] On March 11, 1834, Pennsylvania governor George Wolf signed a license authorizing the Bethlehem Turnpike Road Company to erect many of its gates.

[19] During a three-decade period after the system was created, the pike was designated as Pennsylvania Route 12 (PA 12) from Bethlehem to Center Valley.

[21][22] North of Philadelphia, US 309 was designated on the newly built Fort Washington Expressway, east of the original alignment on the Bethlehem Pike.

[23] Following the commission of the route, PA 309 was moved to a newly constructed freeway, bypassing Sellersville, and west of the Bethlehem Pike.