The mining claim patent process was much less rigorous in the early days of mining when nearly anyone willing to expend the $500 on “patent improvements,” pay for a mineral survey, and pay the statutory purchase price could patent a mining claim very easily. Over time, the United States government has grown increasingly reluctant to patent mining claims and to allow mining activities to occur on unpatented federal public domain lands. The U.S. government argues that its reluctance to allow mining is simply an environmental concern. However, the U.S. tightening of private mining upon federal lands also coincides with a period of significantly rising mineral values. In the early 1990s, the U.S. government used delay tactics in the patent application process followed by an absolute moratorium on patent application approvals in the mid-1990s. The U.S. began gradually imposing arguably-excessive occupancy and environmental regulations around this time as well, increasing the cost of mining operations significantly. In the early 2000s the U.S. began utilizing a dormant trap in the General Mining Act—a combination of valuable discovery, use, and mine-to-mill site provisions—to retroactively invalidate most of the remaining unpatented mining claims as untenable under the Marketability Test. The U.S. also sought to prevent relocation of such retroactively invalidated claims by currently withdrawing federal lands as national monuments under the Antiquities Act. Claimholders who feel that their claims have been wrongly invalidated and/or denied patenting have looked for redress often by arguing that the government’s actions are unconstitutional. An argument that is more likely to be successful, however, is that the invalidation and withdrawal of an otherwise valid, unpatented mining claim may constitute a compensable Fifth Amendment taking by the U.S. government. This article discusses: (1) an overview of the laws governing U.S. mining claims; (2) the process of locating and maintaining an unpatented claim; (3) the process and requirements of claim patenting; (4) the relative benefits of patenting; (5) the federal land withdrawal power under the Antiquities Act; (6) how the a Fifth Amendment takings argument may arise from increased regulatory compliance costs; (7) how a Fifth Amendment takings argument may arise from federal land withdrawals of otherwise valid unpatented mining claims; (8) procedures for litigating mining claim contests; and (9) issues related to a former unpatented claimholder’s standing to sue or intervene in a mining claim contest.