Rugged mountain ranges in southeastern Arizona halted the march of a steel border wall during the first Trump presidency. Wildlife advocates say it shows the importance of animal travel routes.

The Trump administration is seeking bidders for a contract to build about 25 miles of border wall through the San Rafael Valley — a hotly disputed area with one of the longest remaining ...

The Trump administration is fast-tracking wall construction along a critical section of the U.S.-Mexico border, the latest move by the White House to prioritize immigration enforcement.

Walls built along the U.S.-Mexico border over the past several decades are a blight on the landscapes and cultures of the borderlands. Hundreds of miles of wall have been built across protected public ...