Trade between the United States and Mexico increased after Mexican independence. The United States replaced Spain as a transshipment point for British goods, which arrived in Mexico via New York or New Orleans. Flour and cotton were the major U. S. exports to Mexico.
Once Spanish-imposed commercial restrictions were removed, U. S. merchants began landing goods at northern Mexican ports and taking them inland. Much of this trade funneled through Matamoros, near the mouth of the Rio Grande. New Orleans soon became the main port supplying Matamoros, since lighter, shallow-draft ships, suitable for landing along the gulf shore, could sail from there. Ships coming from ports on the U. S. east coast had to be larger to survive the rigors of the Atlantic. In Matamoros, U. S. merchants unloaded American and European goods and returned with cowhides, mules, wool, and coins. Between 1820 and 1837, as a result of commercial restrictions being removed, the population of Matamoros surged from 2,320 to 16,372.22
Charles Stillman, of a Connecticut mercantile family, was one of the foremost Matamoros traders. He promoted his trading there, which he began in 1828, by declaring: “There’s nothing down there but the Rio Grande. There’s nothing across the Rio Grande but Matamoros. There’s nothing in Matamoros but the gateway to all Mexico for cotton, hides and gold!”23
In 1835, U. S. exports to Mexico reached $9 million, or 7 percent of all U. S. exports. U. S. imports from Mexico were not as significant. Before the Mexican—American War, Mexico only supplied about 1 percent of U. S. imports. As conflict over Texas intensified, trade between the two nations declined and remained low for decades.24