The term 'PORT IN THE KEYSTONE ST.' is solved by the crossword answer 'ERIEPA, ' which is a six-letter word. Erie, Pennsylvania is a city located on the south shore of Lake Erie and is the fourth most populous city in the state. It is known as the 'Flagship City' because of its status as the home port of Oliver Hazard Perry's flagship Niagara in the War of 1812. The city is also known as the 'Keystone State' due to its location at the center of the original 13 colonies.