Since Texas became a state, the Rio Grande has marked the border between the U.S. and Mexico. But, like rivers do, it moved. In 1964, the U.S. finally gave back 437 acres of land.
Ever since Texas became a state, the river has been the border between the two countries. But rivers can move — and that’s exactly what happened in 1864, when torrential rains caused it to jump its banks and go south. Suddenly the border was in a different place, and Texas had gained 700 acres of land called the Chamizal (pronounced chah-mee-ZAHL), so named for a type of plant that grew there.