Matamoros, officially known as Heroica Matamoros and formerly named San Juan de los Esteros Hermosos, is a city in the northeastern Mexican state of Tamaulipas. It is located on the southern bank of the Rio Grande, directly across the border from Brownsville, Texas, in the United States. Matamoros is the second largest and second most populous city in the state of Tamaulipas. As of 2010, Matamoros has a population of 489,193. If its floating population is included in the census count, however, the population of Matamoros can reach up to approximately 700,000 habitants. In addition, the Matamoros–Brownsville Metropolitan Area has a population of 1,136,995, making it the 4th largest metropolitan area on the Mexico–US border.