Belfast (/ˈbɛl.fɑːst/ or /ˈbɛl.fæst/; from Irish: Béal Feirste, meaning "mouth of the sandbanks") is the capital and largest city of Northern Ireland. Most of Belfast, including the city centre, is in County Antrim, but parts of East and South Belfast are in County Down. It is on the flood plain of the River Lagan.