During the first half of the war, the Union Navy had successfully blockaded many Southern ports along the Gulf Coast. Cotton trade was a major economic asset for Texas and the whole Confederacy. Initially cotton was transported to Brazos Santiago Pass at the delta of the Rio Grande and exported from Port Isabel. Union forces captured this port and trade was moved inland to Brownsville, Texas. From Brownsville goods were transported across the border to Matamoros and from there to neutral ports along the Mexican coast.