Ciudad Acuña, also known simply as Acuña, is a city located in the Mexican state of Coahuila, at 29°19′27″N 100°55′54″W and a mean height above sea level of 271 m (889 ft). It stands on the Rio Grande, which marks the U.S.-Mexico border, and offers two border crossings via Lake Amistad Dam International Crossing and Del Río-Ciudad Acuña International Bridge with the neighboring city of Del Rio in the U.S. state of Texas. It serves as the municipal seat of the surrounding municipality of Acuña. The 2017 estimated city population was 201,778, whereas the municipality's population was 214,616. The city is the fourth-largest in the state of Coahuila and the fastest-growing city in Mexico. The area is served by the Ciudad Acuña International Airport.

Coahuila, formally Coahuila de Zaragoza, officially the Free and Sovereign State of Coahuila de Zaragoza, is one of the 32 states of Mexico.