The Imperialists now controlled the central Mexican states, containing its major cities, two thirds of the population, rich mines and agricultural lands, and the main centers of manufacturing and trade. The Republicans still controlled the sparsely populated frontier states of the north, where President Juarez still led his government-in-exile in the city of Monterrey. These northern states granted them the considerable revenue coming into the Pacific ports of Manzanillo, Mazatlan, and Guaymas. Arms also flowed in from the U.S. states California and Texas along with mercenaries.
