List of proposed national monuments of the United States
The President of the United States can establish a national monument by presidential proclamation, and the United States Congress can by legislation. The Antiquities Act of 1906 authorized the president to proclaim "historic landmarks, historic and prehistoric structures, and other objects of historic or scientific interest" as national monuments. Interior Department memorandum. In a 2010 "Not for Release" memorandum by the United States Department of the Interior, 14 areas were listed in the "Prospective Conservation Designation" attachment as "good candidates for National Monument designation under the Antiquities Act". Those areas are  included in the lists below, shaded bluish-green. In subsequent attachments in the same draft, "areas worthy of protection that are ineligible for Monument Designation and unlikely to receive legislative protection in the near term" and "cost estimates" of "high priority land-rationalization efforts" were listed.