One of Pennsylvania's youngest Interstate designations, chronologically speaking, the actual expressway first appeared on the 1969 Department of Highways map.  However, it would be another 15 years until it would receive the I-180 designation. 

Construction began in 1969 on the section from Interstate 80 to Exit 10 south of Muncy.  The first segments of this Interstate were completed in 1971 when the sections from Interstate 80 to Exit 1 and Exit 5 to Exit 10 opened to traffic.  That same year, construction began on the segments from Exit 10 to Exit 15 and Exit 27B to Exit 28.  The next section to open was from Exit 1 to Exit 5 in 1972.  Construction began in 1972 on the sections from the Market Street Bridge to Exit 27B and Exit 28 to Exit 29.

No new sections would open until 1974 when not one, but two opened to traffic:  Exit 10 to Exit 15 and Exit 27B to Exit 28.  The US 15 designation was moved off of Williamsport's streets onto the latter section.  A year later, the section between Exit 28 and Exit 29 opened to traffic while construction commenced on the Exit 15 to Exit 23 section.  In 1977, the section from Exit 15 to Exit 23 opened to traffic.

Vehicles would not be riding on a new segment until 1980 when he next section between Exit 25 and Exit 27B was completed.  The final section to be built began in 1982 and opened to traffic two years later.  Upon completion, the highway received the Interstate 180 designation.  This was not the first time an expressway in Pennsylvania used that designation, as it used from 1958 to 1963 to designate the current Interstate 176 in Berks County.

On June 18, 2001, PennDOT began placing exit numbers on this Interstate as a part of the exit renumbering.  Even though there were blank tabs on the signs for years, the exits were never numbered.

Links:
Exit Guide
Interstate 180 Ends
Interstate 180 Pictures
Interstate 180 (Decommissioned)
I-180 Interchange Browser - Tim Reichard
Interstate 180 - Andy Field/Alex Nitzman
Interstate 180 - Scott Oglesby
Interstate 180 Pictures - Andy Field/Alex Nitzman

INFORMATION