Laredo It is a town in and county seat of Webb County, Texas, USA, on the north bank of Rio Grande in South Texas, across from Nuevo Laredo, Tamaulipas, Mexico City. The economy of Laredo is focused upon Mexico's foreign trade. Many big carriers have a plant in Laredo. The city is on the southern end of I-35 making it close to the northern Mexican factories. It has 4 international bridges and 1 rail bridge. The population of the city is more than 236,091, making it the tenth most populous city in the State of Texas and the third most populated on the Mexican frontier.