Izabal is bordered to the north by the nation of Belize, to the north east by the Gulf of Honduras, to the east by the nation of Honduras. Izabal by the Guatemalan departments of Peten to the north west, Alta Verapaz to the west, and Zacapa to the south.
The department of Izabal is around Lago Izabal or Lago de Izabal, Guatemala's largest lake (about 48 km long and 24 km wide, with an area of about 590 km square). The Spanish Colonial era Fort of San Felipe, now a Guatemalan national monument, overlooks the point where the lake flows into the Rio Dulce. The small town of Izabal is on the south shore of the lake; before the construction of the ports of Livingston and Puerto Barrios in the 19th century this was Guatemala's main Caribbean Sea port and was the original seat of Izabal department, but now Izabal town is a remote village that gets little traffic.
From the area around Lake Izabal, the Department of Izabal stretches along the Rio Dulce to the coast of the Caribbean Sea.
The department of Izabal includes the ports of Puerto Barrios (the departnmental seat) and Livingston. Other municipalities in Izabal are El Estor, Los Amantes, and Morales. Izabal also includes the Pre-Columbian Maya ruins of Quirigua.