Laredo is the county seat of Webb County, Texas, United States, located on the north bank of the Rio Grande in South Texas, across from Nuevo Laredo, Tamaulipas, Mexico. According to the 2010 census, the city population was 236,091 making it the tenth most populous city in the state of Texas and 3rd most populated on the United States-Mexican border, after San Diego, California and El Paso, Texas. Laredo is part of the Laredo-Nuevo Laredo Metropolitan Area with an estimate population of 636,516. Laredo's economy is based on international trade with Mexico. Most major transportation companies have a facility in Laredo. Laredo's location along the southern end of I-35 close to the manufacturers in northern Mexico promotes its vital role in trade between the two nations.