Ulster City is a term used to refer to the city of Derry, which is located in Northern Ireland. It is the second-largest city in the country and is the fourth-largest city on the island of Ireland. Derry is the county town of County Londonderry, one of six counties that make up Northern Ireland. The city has a long history, having been founded by the Irish in the 6th century. It is known for its strong cultural identity and is home to a number of important historical sites.