This seat is the political home of Northern Irelandís First Minister, David Trimble, who won it in a 1990 by-election.
The northern half of the seat takes in the whole of Craigavon District Council, which includes the towns of Portadown and Lurgan, as well as the southern shores of Lough Neagh.
The southern half takes in part of Banbridge District Council, including the town of Banbridge itself, with the constituency name being taken from the River Bann, which flows into Lough Neagh.
Portadown is best known to outsiders because it encompasses Drumcree Parish Church and the Garvaghy Road, site of the most contentious annual Orange March. In 2000, for the third year running, Orangemen were not allowed to march down the mainly nationalist Garvaghy Road, and much violence was seen, with water cannons being used on protesters for the first time in decades.
Mr Trimble won last time with a reduced vote share due to the appearance of a DUP candidate, but he nevertheless won with a majority of nearly 10,000.