Pennsylvania was one of the original 13 colonies. As such, Pennsylvania was not acquired but one of the founding states of the United States.
it aquuired on 1783
The United States did acquire the Midway Islands through imperialism. The Midway Islands was initially un-owned and had no coaling station.
By steady encroachment backed up by heavy handed militias and the US Army.
It was admitted to the Union in 1787
US bought it from Mexico.
The US has never acquired Spain.
From France.The french.
its the 49 state