Northern Ireland is home to two major rivers, the Lagan and the Bann. The Lagan is a 5-letter river that flows through Belfast and into the Irish Sea. It is the longest river in Northern Ireland and is an important source of water for the region. The Bann is a 4-letter river that flows from the Mourne Mountains to the Atlantic Ocean. It is the second longest river in Northern Ireland and is a popular destination for fishing and other recreational activities. Both rivers are important to the economy and ecology of Northern Ireland.