Trans-Rio Grande use of outer folded lettersheet to Sr. D. José San Román, Brownsville [Texas] with bold fancy double-oval handstamp of ADMINISTRATION / DEL CARRO (railroad) / DE CORREOS and FRANCO and “Enero 19” at bottom (January 19). Originated from Matamoros, Mexico. Example of mail carried across the Rio Grande from Matamoros to Brownsville, well-known correspondence. $850.

The only international frontier between the Confederacy and a neutral country was formed by the Rio Grande River. This border between southwest Texas and northern Mexico represented a conduit for supplies and mail that could circumvent the Federal blockade of the Confederate coastline. Mail was exchanged across the Rio Grande throughout the war, mostly between commercial correspondents in Mexico and Texas. Full explanation of this is explained in the award-winning book Special Mail Routes of the American Civil War: A Guide to Across-the-Lines Postal History by Steven C. Walske and Scott R. Trepel.

José San Román was a merchant, banker and broker in the contraband cotton trade of the Civil War. He came to America in the late 1830s and settled in New Orleans. In 1846, San Roman moved to Matamoros and established a dry-goods firm. By 1850, the business extended across the Rio Grande to the newly incorporated town of Brownsville, Texas. San Roman prospered and expanded his business into commercial credit, real estate and cotton brokerage. By 1860 San Román moved to Brownsville and with his partners monopolized credit services to smaller merchants, forcing many of them out of business. During the Union blockade, San Román became a key figure in the contraband trade in Bagdad, Brownsville, and Matamoros.   His firm served as a brokerage house for hundreds of cotton farmers west of the Mississippi River. He moved back to Matamoros in the early 1860s and sold cotton wholesale to textile firms in New York, England, and Germany, thereby avoiding the interference of U.S. military and civil authorities on the Texas side of the Rio Grande. By 1870, he was considered one of the wealthiest men in South Texas.