Piedras Negras, Coahuila

Piedras Negras is a city in Coahuila state, Mexico, located at 28.71° N, 100.53° W. It borders on the town of Eagle Pass, Texas, USA, across the Rio Grande or Río Bravo. In 2003 Piedras Negras had an estimated population of 132,900 people.

The city was founded in 1849. It was renamed Ciudad Porfirio Díaz in 1888, in homage to President Porfirio Díaz, but it reverted to its original name following the Mexican Revolution.

On 4 April 2004, the Rio Escondido broke its banks and some 80 residents of the Piedras Negra area were killed by or disappeared in the resulting flash floods. See: BBC coverage.