Interior Secretary Ryan Zinke said Tuesday evening that President Trump has authorized him to review any national monument created since Jan. 1, 1996, that spans at least 100,000 acres “to make sure the people have a voice” in which lands receive the highest level of federal protection.
Trump will sign an executive order authorizing the review Wednesday at the Interior Department, a move that could prompt changes to areas designated not only by former president Barack Obama but also George W. Bush and Bill Clinton. Each created multiple monuments under the 1906 Antiquities Act, which gives the president wide latitude to safeguard federal land that faces threats...
...While Zinke did not identify which designations the administration considers the most problematic, the review has been specifically crafted to encompass national monuments in Utah: Grand Staircase-Escalante, which Clinton declared in 1996, and Bears Ears, which Obama declared last December.
Longish article but worth a read if this topic is of interest to you. I cannot find a full list of the two dozen monuments referenced in the title.