No US president ever revoked a national monument's status. Trump might

U.S. Interior Secretary Ryan Zinke will recommend on Aug. 24 whether to eliminate or shrink nearly two dozen national monuments, creating the first major test for a 111-year-old law that gives presidents the power to protect swaths of public land.

Zinke is expected to recommend that at least some of the national monuments under review - which were all created since 1996 - be rescinded or shrunk in size, responding to an order by President Donald Trump, who believes there should be greater opportunity to increase local resource development and economic opportunities.

Any recommendation of reductions could herald a move into unchartered territory.

Under the Antiquities Act, a president can declare certain areas of historic or scientific interest a national monument. However, no president has ever revoked a previous designation ...

https://www.cnbc.com/2017/08/20/no-us-president-has-ever-revoked-a-national-monuments-status-trump-might-be-the-first.html