In 1952, the southern terminus was moved from PA 72 at Prince Street via Liberty Street and Lititz Avenue to its current location.  In 1962, the northern terminus was moved from US 22 in Bethel to its current location.

In November 2000, PennDOT began studying an effective bypass of Schaefferstown by initiating preliminary engineering and environmental studies.  Since the 1970s, residents have demanded a bypass be built to take the strain of vehicles passing through the borough off the streets.  In 2009, PennDOT requested approval to condemn 5.8 acres of Leon Kline's farm, but the Agricultural Lands Condemnation Approval Board denied the request.  The state appealed to the Commonwealth Court, which concurred with PennDOT argument there was no feasible alternative on September 1, 2010.  Another property that was in the right-of-way was a house at the intersection of PA 419, PA 501, and PA 897 which was moved on June 8, 2011.  The house was spun around and moved back 50 feet into a field, and the moving costs were paid for by the homeowner.  The $7.9 million project officially came to an end on September 9, 2013 when the new alignment opened to traffic.

Signed in the current location in 1941.

In 2004, the eastern terminus was moved from Unionville to Wingate.

Originally signed on the current PA 97 alignment between the intersection with that route to Erie from 1928 until 1932.  In 1931, the route was under construction from US 6 to Erie.

Signed on its current alignment in 1932.

In 1940, the route was moved onto its current alignment from Bethlehem to Moorestown and the southern terminus moved from Newburg to Bethlehem.

In 1971, the northern terminus was moved from PA 115 in Wind Gap to its current location.  In 1974, the southern terminus was moved from Elizabeth Avenue in Bethlehem to its current location.

A median was installed in 1993 from US 22 to Hanoverville Road.

In 1959, the route from the Maryland state line to Sticks was completed and the designation moved onto that part in 1966.  When this happened, the southern terminus was moved from New Freedom.

In 1947, the southern terminus was moved from Morganza to its current location.  In 1954, the northern terminus was moved from Crafton via Noblestown Road to Bridgeville at PA 50.  In 1972, it would be moved yet again, that time to its current location.

In 1975, construction began on the Newtown Bypass and opened in 1977.

In 1930, the route was paved from Dora Road to Grange.  In 1932, the route from Mayport to Ringgold was paved.  In 1936, the section from PA 28 to Mayport was paved.

The northern terminus was moved from Pine Grove Mills to Bellefonte in 1941.  The route was paved from Rishel Hill Road to PA 550 in 1946.

In 1955, the western terminus was moved to PA 167 from Kingsley.  In 1956, the western terminus was moved from PA 167 via Main Albert Mountain Road.

The winter of 2014, as well as truck traffic from the natural gas fields, was not a kind one to the route in Susuquehanna County especially between Gibson and New Milford.  Repair crews contracted by Cabot Oil and Gas began to make repairs and resurfacing the roadway on February 25, 2014 and concluded before March.  A company spokesperson said that even though it is a state-owned highway, it was in their and the community's best interest.

In 1961, the northern terminus was moved back again to the border.

On November 12, 2022, a retaining wall holding South Water Street in Bellefonte between Mill and West High streets collapsed into Spring Creek due to erosion below and behind the wall from high water and general deterioration.  Southbound traffic was moved to the northbound lane, while northbound traffic was detoured along Stoney Batter Road, South Spring Street, West Bishop Street, North Allegheny Street, and West Linn Street.  PennDOT Centre County Maintenance began placing temporary shoring and installing a rock buttress to stabilize the slope on November 28 with the work completed on December 1.  This temporary fix allowed the street to reopen to both directions of travel.  Work on a permanent fix will begin on April 10, 2023 and include removal of the temporary wall, construction of a new retaining wall, resurfacing, new pipes and inlets, concrete curb and sidewalk, pavement markings, and miscellaneous items.  The $393,000 emergency project is expected to be complete by August 7.