Ciudad Juárez, commonly referred to as just Juárez (Lipan: Tsé Táhú'ayá), is the most populous city in the Mexican state of Chihuahua. It was known until 1888 as El Paso del Norte ("The North Pass"). Juárez is the seat of the Juárez Municipality with an estimated population of 2.5 million people. It lies on the Rio Grande (Río Bravo del Norte) river, south of El Paso, Texas, United States. Together with the surrounding areas, the cities form El Paso–Juárez, the second largest binational metropolitan area on the Mexico–U.S. border (after San Diego–Tijuana), with a combined population of over 3.4 million people.