More recently, that same type of shift happened when a massive flood hit in the 1800’s. The river on the north side of San Elizario and Socorro overflowed, and split into a new path below them. In fact, for nearly a decade most of today’s “Lower Valley” was part of a 20 x 4 mile island. That area was the original epicenter of El Paso del Norte and is where a lot of our history takes place. Some of the earliest Paseños, as well as some of our oldest residents, still affectionately refer to the area as “la isla.”
While modern cartography and GPS made it easy to portray rivers and boundaries as steadfast lines, it’s important to remember that rivers move. Before the Elephant Butte dam was built in the early 20th century, the Rio Grande would often change course over time. For example, during a majority of its existence the river has laid on the west side of the Franklin Mountains. Yet, for a prehistoric period, it flowed on the eastern side of the rift zone and helped shape the “Anthony Gap.”

Changing River