Granite Rock Company (Granite) (plaintiff) held unpatented mining claims in a national forest. The United States Forest Service (USFS) approved Granite’s mining plan, and Granite began mining operations. Under California law, a company mining in California’s coastal zone was required to obtain a permit from the California Coastal Commission (Commission) (defendant). The Commission told Granite to apply for this permit. Granite filed suit in the United States District Court for the Northern District of California, seeking to enjoin the Commission from requiring the permit. Granite argued that the California law was preempted by USFS regulations and federal land-use statutes and regulations, including the Federal Land Policy and Management Act and the National Forest Management Act (Acts) and all ensuing regulations. The USFS regulations had been implemented in part to ensure that unpatented mining operations were conducted with limited environmental impact. However, the USFS regulations acknowledged the existence of state laws and stated that certification by state agencies of compliance with similar state mining laws and regulations would “be accepted as compliance” with the USFS regulations. The Commission argued that it would not prohibit Granite’s mining, but merely sought to regulate the mining. Granite filed a motion for summary judgment. The district court denied Granite’s motion and dismissed the claim. The United States Court of Appeals for the Ninth Circuit reversed, finding that California’s permit requirement was federally preempted. The United States Supreme Court granted certiorari.