In 1940, the section between Highland Road and Bridge Road was paved.

In 1940, the section from Swede Hill Road to Maple Hill Road was paved.

In 1941, the section between Jackson Center and Perrine Corners was paved.

In 1940, the section from Game School Road to PA 949 was paved.

In 1938, the section from Morgan Run to Old Erie Pike was paved and from there to Twoey Run Road was improved.  The following year that section was paved.

The southern terminus was moved from US 322 east of Woodland to PA 350 in Sandy Ridge in 1946.

In 1968, the route was moved from US 322 onto its own alignment between Bigler and Woodland.

PA 970 used to follow a routing from US 322 to Woodland, through Pine Top, south past Bigler, and met its current routing west of Wallaceton without joining with US 322 to form a multiplex.  In 2002, the designation was moved to follow SR 2034 to multiplex with US 322 from Wallaceton to Woodland to continue north.

In 2005, the southern terminus was moved from Sandy Ridge to its current location.

In 1941, the section from US 19 to Boyce was improved.  In 1946, the route's southern terminus was moved to its current location from US 19 near the Washington County line.  In 1949, the route was paved between North Branch Road and Lutz Road.  In 1963, the route was paved between William Penn Highway and Imperial.

In 1962, the route was moved to Potato Garden Road, Washington Road, and Moon Clinton Road from another highway that is now under the airport facility.

In 1976, the northern terminus was moved from PA 51 at Narrows Run Road to its current location.  The former path followed Potato Garden Road, Washington Road, and Moon Clinton Road.

In 1951, the northern terminus was moved from US 30 in Clinton to the William Penn Highway.

In 1965, the northern terminus was moved to its current location from William Penn Highway to its current location.

In 1940, the route between Old Cemetery Road and Locust Knob was paved, as was the future route between US 22 and Rushwood Road.

In 1952, the route was moved from Rushwood Road to its current alignment north of New Alexandria.  In 1954, the route was widened from Lloyd Avenue Extension to Latrobe.  In 1956, the route was moved onto the new interstate between PA 201 and PA 51.  In 1959, the southern terminus was moved from PA 201 at the Donora/ Monessen interchange of I-70 to its current location.

In 1962, a median was installed from Latrobe to Latrobe-Derry Road.

In 1976, the route was changed to enter Mount Pleasant on its current route from the former multiplex with PA 819 from north of the town to PA 31.

In 1998, extended to meet PA 819 near Salina from its former terminus at PA 156.

Beginning in 2000, PennDOT began studying improvements to the corridor from East Huntingdon Township to north of US 22.  The study is currently in Step Four of the ten step Transportation Development Process.  One solution could be the revival of the Laurel Valley Expressway plan.

This route holds a special place for me, in that I grew up three-tenths of a mile off of it.

In 1936, the southern terminus was moved from the Borough of Livermore to PA 31 in Laurelville.  In 1938, the section from Weltytown to Lycippus was paved.

In 1946, the southern terminus was moved from Laurelville to US 119.

In 1951, the route became disconnected across the Conemaugh River.

In 1960, the northern terminus was moved from PA 680, currently PA 217 via Livermore Road in Westmoreland County and Grange Road in Indiana County to its current location.  This created a disjoined route between the two sides of the Conemaugh River.

Another route close to me since I grew up just a few feet off of PA 982.  On a side note, the bridge that carries PA 982 over the Loyalhanna Creek was featured in a Rolling Rock commercial in the late 1990s.

Signed in 1980 in its current location.

From July 24 to July 28, 2002, the eyes of the world focused on the intersection of this route and Haupt Road near the southern terminus.  This was the location of the Quecreek Mine accident, and where the rescue effort unfolded. 

Signed in the current location in 1940.

A median was installed in 1954 at US 22.  In 1955, the southern terminus was moved from Union Avenue to the Lehigh Valley Thruway.

In 1940, the northern terminus was moved from PA 68 at Zeigler Road via Willoughby Run Road to its current location.  In 1941, the section from Phillips Street to Conway Wallrose Road was paved.