While noticing a “Penna Turnpike” sign, I thought, “oh yeah, why is it called Penna?” I’ve heard “Penn” used for the university and mostly have seen “PA” for Pennsylvania’s abbreviations. After posting the “Penna Turnpike” sign, asking this very question on TikTok, an informed commenter enlightened me with the reason why, and I confirmed this information via the USPS website.
Until 1963, mail was distributed to states via their own 2-4 letter abbreviations, from things like “Penn” to “NY.” New York has always been shortened to “NY,” but some states, like Hawaii and Idaho, used their entire state name. Since “addressing equipment” could only hold 23 characters at the bottom, any abbreviations 3+ letters long wouldn’t fit anymore. When zip codes were invented, this equipment needed to be able to hold these 5 numbers in any instance, thus all state abbreviations were changed to be only 2 letters long in October of 1963. Areas like DC, NY, and LA got to keep the abbreviations they always used while Penn changed to PA, Hawaii to HA, and Idaho to ID.
Now we go back to our original question: if all states were forced to use a two letter abbreviation, why does Pennsylvania still use Penna on their turnpike signs? They do occasionally call it the PA turnpike, enough so that there’s an actual PATurnpike.com, which is where I learned that it’s also called “America’s First Superhighway.” This now 360 mile controlled-access highway stretches across the entire state, has 15 service plazas along the route, and is 82 years old! I got very familiar with these service plazas: each one has fast food restaurants, gas, a convenience store, and occasionally ATMs, cell phone charging stations, restrooms and wi-fi. (I’ll personally add that the fact that restrooms are at only “some” of them and these stores and restaurants do have a closing time was something I learned the hard way. If you’re traveling along the Penna Turnpike, make note when signage specifies that there’s actually public restrooms.)
This popular and well traversed highway was planned in 1930 and opened officially in October of 1940. The original goal of the Penna Turnpike was to improve transportation through the Pennsylvania Appalachian Mountains but was so impressive with its design, efficiency, and engineering, it became the model and inspiration for the current federal interstate highway system. One reason for this is possibly that the engineers consciously desired a consistent experience through the drive. The PA Turnpike also gave faster routes than the traditional highway system, by allowing people to travel THROUGH the mountains (via tunnels) instead of circling up and around each mountain to travel through them.
Other fun things about the Penna Turnpike? It’s the backdrop for movies such as The Mothman Prophesies, The Next Three Days and Love and Other Drugs. The abandoned Penna Turnpike is also where the post-apocalyptic film The Road was filmed!