This is a very important question to understand before making a trip to Belfast. In some instances, Ireland refers to the entire geographical mass of the whole island. Within the island of Ireland, there are two distinct countries with their own governments. Most of of the island is under the authority of the government of the Republic of Ireland. Confusingly, the Republic’s official name is simply Ireland, but it is still one of two countries on the landmass. The Republic of Ireland is not part of the United Kingdom, but is a full member of the European Union.
Up in the northeastern corner sits the country of Northern Ireland, which has its own government. Northern Ireland is part of the United Kingdom, alongside England, Wales and Scotland. Belfast is the largest city and capital of Northern Ireland.
The history of the two countries is long, turbulent and violent, stretching back several hundred years. However, peace has ruled over both countries for the past two decades, as much of the earlier violence ended with the Good Friday Agreement in 1998.