The Port Plaza was located on Lafayette Road (U.S. Route 1) in Portsmouth where a Walmart store is today. In fall 1972, an IGA Foodliner supermarket opened at the Port Plaza. By summer 1974, the supermarket changed name to become a Pic'n Pay.  Pic'n Pay also had a supermarket at Plaza 800 in Portsmouth.  The latter eventually became a Shop'n save and is still there today as a Hannaford.

Back at the Port Plaza, the main anchor was a Mammoth Mart discount store. By 1974, the store became The Mart only to close a few years later.  Grossman's Hardware had a store near or at the Port Plaza.  It closed in the 1990's.  By then, Walmart opened a store on the site of the Port Plaza.  A Joker's Fun Center opened there in the only remaining building of the Port Plaza (the former supermarket).  The latter was demolished recently to create more space for Walmart to transform their store into a Supercenter.