I assume you mean the Chair of St. Peter, which is currently
held by Pope Benedict the XII, living in Vatican City. Country is
located inside the city of Rome.
There are many of them around the world. Most important are the
ones in Ireland, like St. Patrick's Cathedral in Armagh, the seat
of the Catholic Church in Ireland.
The seat, or administrative center of the RCC is in Vatican
City, Rome, Italy.
There are individual Catholic Churches in almost every town and
city in the US.