Not a single mile.
Courtesy of the Washington Examiner:
The Trump administration has not installed a single mile of new wall in a previously fenceless part of the U.S.-Mexico border in the 30 months since President Trump assumed office, despite his campaign promise to construct a “big beautiful wall.”
In a statement last week, U.S. Customs and Border Protection, the federal agency overseeing border barrier construction, confirmed that all the fencing completed since Trump took office is “in place of dilapidated designs” because the existing fence was in need of replacement.
The agency said that it had built 51 miles of steel bollard fence with funding that was set aside during fiscal 2017 and 2018. But while the funding was meant both to replace outdated walls and to place barriers where there previously had been none, the government has only completed the replacement projects. The projects to secure areas with no fence are still in the works.
Keep in mind that Trump has repeatedly bragged that there have been miles of new border wall built since he took office.
Not one single mile has in fact been built.