Cortés is one of the 18 departments into which the Central American nation of Honduras is divided. The department covers a total surface area of 3,954 km² and, in 2005, had an estimated population of 1,365,497 people, making it the most populous department in Honduras. The Merendón Mountains rise in western Cortés, but the department is mostly a tropical lowland, the Sula Valley, crossed by the Ulúa and Chamelecon rivers.