Most of the coffee exported was grown around the main centers of population in the Central Plateau and then transported by oxcart to the Pacific port of Puntarenas after the main road was built in 1846. By the mid-1850s the main market for coffee was Britain. It soon became a high priority to develop an effective transportation route from the Central Plateau to the Atlantic Ocean. For this purpose, in the 1870s, the Costa Rican government contracted with U.S. businessman Minor C. Keith to build a railroad from San José to the Caribbean port of Limón. Despite enormous difficulties with construction, disease, and financing, the railroad was completed in 1890.