The Antiquities Act of 1906 (54 U.S.C. SSSS320301-320303) authorizes the President to proclaim national monuments on federal lands that contain "historic landmarks, historic and prehistoric structures, and other objects of historic or scientific interest." Monument proclamations typically seek to provide protections to federal lands and resources. The President is to reserve "the smallest area compatible with the proper care and management of the objects to be protected." The act does not further specify the process to be used by Presidents in proclaiming monuments. From 1906 to the date of this report, Presidents have established 157 monuments and have enlarged, diminished, or otherwise modified previously proclaimed monuments. In 2017, the Trump Administration engaged in a review of certain national monuments proclaimed by Presidents under the Antiquities Act since 1996. Presidential establishment and modification of national monuments has sometimes been contentious, and litigation and legislation have been pursued. Criticism has centered on the size of the areas and the types of resources protected; the effect of monument designations on land uses; the inclusion of nonfederal lands within monument boundaries; and the lack of requirements for public participation, congressional and state approval, and environmental reviews in the Antiquities Act, among other issues. Monument advocates believe the President needs authority to act promptly to protect valuable resources. They assert that the public has supported and courts have upheld presidential designations and that many initially controversial designations have come to be widely supported. Congress continues to face a variety of issues related to national monuments. Whether to establish, amend, or abolish national monuments is of current interest. Congress has broad authority to take these actions, and has created national monuments on federal lands and has increased and decreased monument sizes on numerous occasions. In establishing and amending national monuments, questions for Congress include the optimal size of the areas to be protected and the extent to which various land uses and activities will be allowed, barred, or restricted. In the past, Congress, but not the President, has abolished some monuments and converted others to different protective designations, such as national parks. Whether the President has authority to abolish national monuments is debated and has not been tested in courts. Congress also oversees presidential exercise of authority to proclaim monuments and has considered measures to alter this authority. Controversy over presidential monument designations is one component of a broader debate over federal land ownership and management. Discontent over federal land management has sometimes led to conflict, as in the 2016 takeover of the Malheur National Wildlife Refuge in Oregon. A central issue in this debate is the extent to which the federal government should dispose of, retain, or acquire lands. Some stakeholders seek disposal to foster state and local ownership and control over federal lands and resources, especially in the West, where federal lands are concentrated. Advocates of federal land retention and acquisition point to benefits of federal ownership, including protection of resources and public access for recreation. Another focus is the condition of federal lands and infrastructure. Debates also encompass the extent to which federal lands should be developed and/or open to recreation and whether they should be managed primarily to produce local or national benefits. On April 26, 2017, President Trump issued an executive order requiring the Secretary of the Interior to review national monuments established or expanded by Presidents since 1996. The order required review of national monuments where the size at establishment or after expansion exceeded 100,000 acres or where the Secretary determined that the action was taken "without adequate public outreach and coordination with relevant stakeholders." With regard to monument size, the Antiquities Act requires the President to reserve "the smallest area compatible with the proper care and management of the objects to be protected," as noted. The act does not specifically require public outreach and coordination in monument designations. The executive order set out a policy with regard to monument designation, including that designations are made "in accordance with the requirements and original objectives" of the Antiquities Act and "appropriately balance the protection of landmarks, structures, and objects against the appropriate use of Federal lands and the effects on surrounding lands and communities." The review was to determine if the establishment or expansion of post-1996 monuments conformed to the policy in the executive order and to develop any recommendation for presidential actions, legislative proposals, or other actions to carry out the policy. Factors for the Interior Secretary to evaluate in his review were specified in the executive order. They included the requirements and objectives of the Antiquities Act, including that designations be confined to "the smallest area compatible with the proper care and management of the objects to be protected"; whether designated lands are "appropriately classified" as historic landmarks, historic and prehistoric structures, or other objects of historic or scientific interest; the effect of monument designation on uses of federal and nonfederal lands inside and outside of the monument boundaries; concerns of affected state, tribal, and local governments; availability of federal resources to manage designated areas; and other factors determined by the Secretary. The executive order required the Secretary to provide an interim report to the President, within 45 days of the executive order's issuance, on Bears Ears National Monument in Utah and other monuments the Secretary determined appropriate. A final report on the secretarial review of monuments was due within 120 days of the issuance of the executive order--August 24, 2017. These reports were to include recommendations for presidential actions, legislative proposals, or other actions, as noted. Most of the post-1996 monuments are managed by agencies within the Department of the Interior (DOI), but some are managed by other agencies (e.g., the Forest Service, in the Department of Agriculture), as shown in Table 1 . The executive order called for the Interior Secretary to consult and coordinate with heads of other federal departments; state governors; and other state, local, and tribal officials. Since 1996, Presidents Clinton, George W. Bush, and Obama have issued 64 monument-related proclamations. Of these, 54 proclamations established monuments (about one-third of all presidentially proclaimed monuments) and 8 proclamations expanded monuments. The remaining two proclamations had other purposes. The total area of the designations and expansions is approximately 774.1 million acres, or about 92% of all monument acreage proclaimed since enactment of the Antiquities Act, as shown in Table 3 . Most of this acreage--762.6 million (98.5%)--is in marine areas designated or expanded by Presidents Bush and Obama, with the remaining 11.5 million acres (1.5%) in terrestrial areas. Of the monuments established and expanded since 1996, it appears that Presidents have established or expanded 26 national monuments exceeding 100,000 acres. These monuments are in 10 states and 4 marine areas. In a May 5, 2017, press release, DOI identified 27 national monuments that would be reviewed under the President's executive order (see Table 1 ). One of the 27 monuments, Katahdin Woods and Waters National Monument, was reviewed based on the adequacy of public outreach and coordination with stakeholders in establishing the monument. The other 26 monuments were reviewed because the size at establishment or after expansion exceeded 100,000 acres. Five of the 27 monuments are marine based, and the Secretary of Commerce was to take the lead in reviewing these monuments. Twenty-two of the 27 monuments are land based, and the Secretary of the Interior led their review. On monuments under review, the Administration sought public comment from May 11, 2017, through July 10, 2017. A total of 2,839,046 comments were received. In summarizing the comments, the Interior Secretary stated that comments "were overwhelmingly in favor of maintaining existing monuments." According to the Secretary, commenters favored monument designations for their economic benefits from increased tourism and to prevent the sale of federal land. By contrast, other commenters supported abolishing or modifying monument designations to allow for a broader array of activities on the lands, among other reasons. The Secretary also held meetings at several monuments in different states to receive input from stakeholders, including elected officials and interest groups. On June 10, 2017, the Secretary of the Interior issued an interim report focused only on Bears Ears National Monument. In the interim report, the Secretary stated that the designation of Bears Ears National Monument "does not fully conform with the policies" set out in the executive order. According to the Secretary, the monument size was not the "smallest area compatible" with care of the objects requiring protection. The Secretary further asserted that some areas within the monument have other congressional or administrative designations, making "unnecessary" their protection under the Antiquities Act; some monument lands would be better managed as other types of designations, such as national recreation areas; some management provisions are too restrictive; and tribes do not have an "adequate role" in managing the monument. The Secretary made several interim recommendations, such as revising the monument boundary. However, he recommended that DOI conclude the full review of monuments before making more specific recommendations for Bears Ears. The final report contained more extensive recommendations on Bears Ears, and these recommendations are discussed below (under " Recommendations in Final Report ") and shown in Table 2 . Before the issuance of the final report, the Secretary of the Interior concluded the review of six monuments: Craters of the Moon, Hanford Reach, Upper Missouri River Breaks, Grand Canyon-Parashant, Canyons of the Ancients, and Sand to Snow. In press releases issued between July 13, 2017, and August 16, 2017, the Secretary stated that no changes were being recommended to these areas. On August 24, 2017, the Secretary of the Interior sent to the President a final report on monuments reviewed, which included recommendations. The document was not publicly released. Instead, the Administration provided to the public a two-page summary of the report. A version of the Secretary's full report, marked "Draft Deliberative--Not for Distribution," subsequently became available to the public through the media. In the final report, Interior Secretary Ryan Zinke stated that each of the reviewed monuments is unique, and that some monuments are currently supported strongly by the local communities. However, some monument designations remain controversial for a variety of reasons, according to the Secretary. Among the controversial aspects of proclaimed monuments, the final report cited the size of the areas, types of objects protected, effect on land uses, extent of public access, sufficiency of public consultation, adequacy of protection of resources, inclusion of private lands within monument boundaries, and "overlap" with other federal land designations. In the final report to the President, the Interior Secretary made individual recommendations for 10 of the 27 monuments that were reviewed. (See Table 2 .) According to the Secretary, these recommendations were made with the concurrence of the Secretary of Agriculture and the Secretary of Commerce. Some Members and stakeholders supported the recommendations, whereas other lawmakers and stakeholders opposed them. The recommendations included amending monument proclamations regarding protection and management of resources, and, for some areas, revising monument boundaries. The Secretary of the Interior called for these changes to be made "through the use of appropriate authority, including lawful exercise of the President's discretion granted by the [Antiquities] Act." Congress has authority to modify management of lands within, and boundaries of, monuments established by presidential proclamation under the Antiquities Act. The Secretary did not fully detail the changes to be made to monument proclamations or identify the precise locations and sizes of the boundary alterations. Rather, the final report provided that "[r]ecommendations for specific monument modifications reflecting the above considerations will be submitted separately from this Final Report should you concur with my recommendations." The number of recommendations per monument ranged from one recommendation for each of three marine monuments (Northeast Canyons and Seamounts, Pacific Remote Islands, and Rose Atoll), to six recommendations for each of two monuments (Bears Ears and Organ Mountains-Desert Peaks). The most common recommendation was to amend the proclamations for specified purposes. For 8 of the 10 monuments, the Secretary recommended amending the proclamations, whereas for the other 2 monuments--Pacific Remote Islands Marine and Rose Atoll Marine--the Secretary recommended either amending the proclamations or making boundary revisions. Six of the 10 proclamations would be amended for several purposes, namely "to protect objects and prioritize public access; infrastructure upgrades, repair, and maintenance; traditional use; tribal cultural use; and hunting and fishing rights." The six monuments are Bears Ears, Cascade Siskiyou, Gold Butte, Grand Staircase-Escalante, Organ Mountains-Desert Peaks, and Rio Grande del Norte. For these six monuments, as well as Katahdin Woods and Waters, the Secretary recommended similar changes to agency management plans or development of plans with these emphases. The other four proclamations would be amended for a primary purpose, either regarding commercial fishing for certain marine monuments (Northeast Canyons and Seamounts, Pacific Remote Islands, and Rose Atoll) or active timber management for Katahdin Woods and Waters. Boundary changes were proposed for four national monuments: Bears Ears, Cascade-Siskiyou, Gold Butte, and Grand Staircase-Escalante. As mentioned, for two additional monuments--Pacific Remote Islands Marine and Rose Atoll Marine--the Secretary recommended either amending the proclamations or making boundary revisions. For all but Grand Staircase-Escalante, the Secretary specified the purposes of the boundary changes, and these purposes differed among the monuments. In the case of Bears Ears, the boundaries would be revised "to protect objects and ensure the size is conducive to [their] effective protection." The Gold Butte boundary change would "protect historic water rights." The Cascade-Siskiyou revision pertained to allowing sustained timber yield and reducing impacts on private lands, whereas the Pacific Remote Islands Marine and Rose Atoll Marine boundary adjustments related to allowing commercial fishing. The final report contained other recommendations for the 10 monuments, some of which recommend additional authority or other action from Congress. As shown in Table 2 , the Secretary recommended that DOI and Congress work together "to secure funding for adequate infrastructure and management needed to protect objects effectively," for six monuments; the President request authority from Congress to enable tribal comanagement of cultural areas, for four monuments; Congress "make more appropriate conservation designations, such as national recreation areas or national conservation areas," for Bears Ears; and DOI work with the Department of Homeland Security to assess risks to border safety in a specified area, and with the Department of Defense to assess risks to operational readiness of nearby military installations, for Organ Mountains-Desert Peaks. In addition to the recommendations for the 10 areas, the final report contained broader proposals. They included changes to the monument designation process to establish standards for public input and processes and to include "clear criteria for designations and methodology for meeting conservation and protection goals." According to the Secretary, these changes to the monument designation process could be made through "legislation, regulations, or internal guidance within the Executive Branch, such as an Executive Order or a Secretary's Order." The Secretary asserted that the Antiquities Act has been used many times for the "proper stewardship of objects of cultural, historic, or scientific interest." He further noted that some additional areas suggested by stakeholders "merit protection and designation" through the Antiquities Act. The final report identified these areas as Camp Nelson in Kentucky, the Medgar Evers Home in Mississippi, and the Badger-Two Medicine area in Montana. The Secretary recommended that these three areas be evaluated for national monument designation. The Secretary recommended that the President ask Congress to take certain actions. They included clarifying the limits of executive authority under the Antiquities Act and the intent of Congress regarding land use in monument areas containing other protective designations. According to the Secretary, DOI has sometimes been too restrictive in implementing monument management plans for protection of monument objects, so as "to impede allowable uses" on monument lands. DOI will review monument management plans and update them as needed to address this issue, according to the final report. Since the enactment of the Antiquities Act in 1906, Presidents have issued 259 proclamations to establish new monuments and to modify national monuments established by earlier presidential proclamation. Such modifications have included enlargement or diminishment of monument boundaries and other changes, as shown in Table 3 . Secretary Zinke's final report does not specifically recommend monument enlargements, and has been generally interpreted as likely recommending reductions instead. Nevertheless, it is worth noting that in the past, Presidents have expanded existing monuments on 76 occasions, as shown in Table 3 . These enlargements were made over the past century, with the first in 1909 and the last in 2017. They were of widely varying acreages and percentages of the sizes of the original monuments. The biggest acreage expansion occurred in 2016, when President Obama enlarged the Papahanaumokuakea Marine National Monument by 283.4 million acres, more than quadrupling the size of the monument to approximately 373 million acres. The largest expansion of a terrestrial monument occurred in 1931, when President Hoover expanded the Katmai National Monument by 1,609,600 acres, a 148% increase over the 1,088,000 acreage at establishment. By contrast, in 1958, President Eisenhower proclaimed the smallest acreage expansion, by adding 0.15 acres to the Tumacacori National Monument. Some monuments have been expanded multiple times. For instance, four different Presidents enlarged the Muir Woods National Monument following its establishment in 1908. Past Presidents also have diminished national monuments, although less frequently than they have expanded them. Specifically, Presidents reduced monuments on 12 occasions, with the first such action occurring in 1911 and the most recent in 1960. The diminishments varied widely in terms of acreages and percentages of the original monument sizes. Acreage reductions ranged from 52 acres, in 1941 for the Wupatki National Monument, to 313,280 acres, in 1915 for the Mount Olympus National Monument, as shown in Table 4 . Percentage reductions varied from 0.03%, in 1912 for the Mount Olympus National Monument, to 89%, in 1912 for the Navajo National Monument. Some monuments have been reduced multiple times. Three different Presidents diminished Mount Olympus National Monument following its establishment in 1909, for example. The final report does not make clear whether the Secretary proposed boundary changes that would both remove areas from one part of a monument while adding acreage to another area of the monument. Since enactment of the Antiquities Act, six presidential proclamations have both enlarged and diminished national monuments, as shown in Table 5 . These proclamations all were issued between 1956 and 1963. They typically added acreage to one area of a monument and removed acreage from another portion of the monument. Of the six proclamations, four removed more land than was added, thus reducing the size overall; one added more land than was removed, for a net gain in land; and one added and removed the same number of acres, resulting in no change in size. The six proclamations reflected varying percentages of change to the original monument sizes, ranging from -20% to +179%. Presidential changes to monument sizes have sometimes occurred after congressional enactment of revisions to monument boundaries/sizes, and have included both enlargement and diminishment of monuments. The Craters of the Moon National Monument, established by presidential proclamation in 1924, offers two examples. In the first example, following congressional removal of areas from the monument in 1936, President Franklin D. Roosevelt further diminished the monument (1941), and then President Kennedy enlarged it (1962). In the second example, following congressional revision in 1996 in the form of enlargement of some areas of the monument and diminishment of others, President Clinton enlarged the monument in 2000. The Pinnacles National Monument provides a third example. In 1976, Congress added areas to the monument; in 2000, President Clinton further enlarged the monument. The final report did not recommend the abolition of any national monuments. The Antiquities Act does not expressly authorize a President to abolish a national monument established by an earlier presidential proclamation, and no President has done so. There have been no court cases deciding the issue of the authority of the President to abolish a national monument. The final report recommends amending monument proclamations regarding resource management. On eight occasions, between 1911 and 2007, Presidents have issued proclamations whose primary purpose was other than to enlarge or diminish monument size, as shown in Table 6 . Two of the eight proclamations appear to pertain to resource management. In 1936, President Franklin D. Roosevelt modified the Katmai National Monument to make the reservations in the earlier proclamations subject to valid existing rights, since maintained. In 2007, President George W. Bush amended the Papahanaumokuakea Marine National Monument regarding conditions for issuing permits for Native Hawaiian practices, as well as to change the name (from Northwestern Hawaiian Islands Marine National Monument). Another two of the eight proclamations, for Great Sand Dunes and Buck Island Reef, revised the descriptions of the areas included in the monuments. The Great Sand Dunes revision followed a resurvey, and the Buck Island revision sought to correct an error. The remaining four proclamations essentially affirmed the monument boundaries. The final report recommended that three areas be evaluated for national monument designation. Since the enactment of the Antiquities Act in 1906, Presidents have established 157 national monuments. Congress, too, has created national monuments on federal lands on numerous occasions under its constitutional authority to enact legislation regarding federal lands. This authority is not defined or limited by the provisions of the Antiquities Act. For instance, Congress could enact legislation providing more land uses than are typical for national monuments created by the President, such as allowing new commercial development, or could choose to provide additional protections. Congress also has modified monuments (including those created by the President)--for instance, by changing their boundaries. Congress has abolished some monuments outright and converted others into different protective designations, such as national parks. Approximately half of the current national parks were first designated as national monuments, for instance.

Summary:
The Antiquities Act of 1906 (54 U.S.C. SSSS320301-320303) authorizes the President to proclaim national monuments on federal lands that contain "historic landmarks, historic and prehistoric structures, and other objects of historic or scientific interest." Monument proclamations typically seek to provide protections to federal lands and resources. The President is to reserve "the smallest area compatible with the proper care and management of the objects to be protected." The act does not further specify the process to be used by Presidents in proclaiming monuments. From 1906 to date, Presidents have established 157 monuments and have also enlarged, diminished, or otherwise modified previously proclaimed monuments through a total of 259 proclamations. Presidential establishment and modification of national monuments has sometimes been contentious, and litigation and legislation have been pursued. Criticism has centered on the size of the areas and types of resources protected; effect of monument designations on land uses; inclusion of nonfederal lands within monument boundaries; and extent of public consultation. Monument advocates believe the President needs authority to act promptly to protect valuable resources. They assert that the public has supported and courts have upheld presidential designations and that many initially controversial designations have come to be supported. In 2017, the Trump Administration reviewed certain national monuments proclaimed by previous Presidents. The effort began on April 26, 2017, with an executive order requiring the Secretary of the Interior to review national monuments established or expanded by Presidents since 1996. The order required review of national monuments where the size at establishment or after expansion exceeded 100,000 acres or where the Secretary determined that the action was taken "without adequate public outreach and coordination with relevant stakeholders." The Antiquities Act does not specifically require public outreach and coordination in monument designations. The review was to determine if the establishment or expansion of post-1996 monuments conformed to a policy set out in the executive order and to develop any recommendation for presidential actions, legislative proposals, or other actions to carry out the policy. The executive order called for interim and final reports on the monuments under review, within specified time periods. The Department of the Interior (DOI) reviewed a total of 27 monuments, one based on the adequacy of consultation and the others based on their size. During the review, the Administration received 2,839,046 comments from the public and visited several monument areas to receive public input. On August 24, 2017, the Secretary submitted to the President a final report on all 27 monuments reviewed. The report, marked "draft," was made public by the news media. It contained recommendations for 10 of the 27 monuments, with between one and six recommendations per monument. The types of recommendations varied. They included amending monument proclamations for specified purposes, changing monument boundaries, agency revision of monument management plans, and seeking authority from Congress for tribal comanagement of cultural areas. The report also contained broader recommendations, including changing the monument designation process, establishing new monuments, and seeking congressional clarification of the limits on executive authority under the Antiquities Act and the intent of Congress regarding land uses of monument areas with other protective designations. Congress continues to face a variety of national monument issues. Congress has broad authority to establish, amend, or abolish national monuments and has done so on numerous occasions, including amending and redesignating monuments proclaimed by Presidents. Congress also oversees presidential exercise of authority to proclaim monuments and has considered measures to alter this authority.