The land boundary between Angola and the Democratic Republic of the Congo is divided into two separate segments, one with the northern Angola enclave of Cabinda and one to the south with the rest of Angola. Both sets of boundaries were defined and demarcated by a multitude of late 19th and early 20th century Portuguese and Belgian colonial agreements. The Cabinda–Democratic Republic of the Congo boundary begins in the Atlantic Ocean and continues for 285 km before reaching the tripoint with the Republic of the Congo. The boundary between the main part of Angola and the Democratic Republic of the Congo is much longer at 2,693 km. It also begins in the Atlantic Ocean in the mouth of the Congo River and follows various west and south trajectories before reaching the tripoint with Zambia. Both sets of boundaries follow a series of rivers and demarcated lines.