From Doug Kerr, on Park Ave. SB just north of State College, with room for a South I-99. If looks could kill...
I-99 and US 220 (and US 322)
US 220 from I-80 to I-180
I-180 and US 220
US 220 north of I-180
PA 150 (old US 220 and part of Alt. US 220)
In my personal collection, installed by an auto club as was the wont in the 1920's. This enamel or porcelain sign certainly dates to the nascence of the US Highway system.