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 236,191 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 and El Paso. Its metropolitan area is the 178th-largest United States metropolitan area and covers all of Webb county, with a population of 250,304. 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. The city's location on the southern end of I-35 close to the manufacturers in northern Mexico promotes its vital role in trade between the two nations. Laredo International Airport is within the Laredo city limits, while the Quetzalcoatl International Airport is nearby in Nuevo Laredo on the Mexican side.