The Department of Homeland Security (DHS) has constructed 42 miles of border wall that has mostly replaced existing barriers rather than extending the physical infrastructure at the nearly 2,000-mile long United States-Mexico border.

In a brief on border wall construction, DHS officials say the agency has completed about 42 miles of border wall, most of which replace existing barriers, since President Trump’s inauguration. About 205 miles of “new and updated border barriers have been funded” since January 2017, the brief states.

Additionally, DHS officials say the Defense Department is set to construct about 131 miles of “of new border barriers in place of dilapidated or outdated designs, in addition to road construction and lighting installation.”

In a breakdown by DHS, about 226 miles of the total 336 miles expected to be constructed is of update primary barriers, updated vehicle barriers, or update secondary barriers. The other 110 miles are designated for “new primary wall” and “new levee wall.”

Still, the mileage of border wall built in areas of the southern border that previously did not have a barrier remains unclear, though sources close to DHS told Breitbart News the figure is low.

Every administration since the early 2000s has replaced border barriers at the U.S.-Mexico border, as the Trump administration has continued doing. The Obama administration, for example, constructed an 18-foot border fence that replaced an existing barrier in the Sunderland Park, New Mexico region.

Meanwhile, the majority of the U.S.-Mexico border has remained open as DHS replaces existing fencing rather than extending border barriers to new land areas that would otherwise have stayed open.

In April, there were nearly 100,000 border apprehensions. This puts illegal immigration at the southern border on track to outpace every year of illegal immigration under former President Obama and take the U.S. back to Bush era levels. At current rates, experts project there to be 863,000 border apprehensions this Fiscal Year, though this only counts illegal aliens who are caught at the border and does not include those who successfully cross.

Likewise, DHS has continued releasing more than 37,000 border crossers and illegal aliens into the interior of the U.S. every month. In the last five months, about 185,500 border crossers and illegal aliens have been released into the country and the vast majority are likely never to be deported.

John Binder is a reporter for Breitbart News. Follow him on Twitter at @JxhnBinder.