City Across the Rio Grande from El Paso: Ciudad Juárez

The Mexican city directly across the Rio Grande from El Paso, Texas is Ciudad Juárez, Chihuahua.

Together they form the Paso del Norte metropolitan area (pop. ~2.7 million), one of the largest binational conurbations. Connected by multiple bridges: Paso del Norte, Stanton, Ysleta, and the Bridge of the Americas.