Most U.S. border land east of El Paso, Tex., is privately owned. To the west, most of the land is owned by the federal government.
The government has built nearly 700 miles of wall and fencing since 2006, mostly on federal land and where the terrain does not provide a natural barrier.
President Trump wants to build a new wall that could cost $25 billion. Eight prototypes, ranging from 18 to 30 feet high, have been tested near the San Diego border.