Berreyesa v. United States was a United States Supreme Court case that dealt with the issue of whether the United States government had the right to take possession of land in California that had been granted to a Mexican citizen by the Mexican government prior to the Mexican-American War. The case was brought by the heirs of the original grantee, who argued that the United States had no right to take possession of the land without compensating them for it. The Supreme Court ultimately ruled in favor of the United States, holding that the Mexican government had no authority to grant land to its citizens in a territory that was not under its control. The Court reasoned that the Mexican government had no right to grant land in a territory that was not under its control, and that the United States had the right to take possession of the land without compensating the grantee's heirs. The Court's decision was significant in that it established the principle that the United States had the right to take possession of land in territories that were not under its control, without compensating the original grantee or their heirs. This decision has been cited in numerous subsequent cases involving the United States' right to take possession of land in territories that are not under its control.

In Berreyesa v. United States, the Supreme Court was asked to determine whether a Mexican land grant made by the government of Mexico in 1843 could be recognized as valid under U.S. law after California became part of the United States following its admission into the Union in 1850. The majority opinion held that such grants were not valid and could not be enforced against subsequent purchasers who had acquired title from the federal government or state governments without notice of any prior claim based on a Mexican grant. Justice Field dissented, arguing that it would be unjust for individuals to lose their property rights due to changes in political boundaries beyond their control and noting that Congress had enacted legislation recognizing certain pre-existing Spanish and Mexican land titles within California's borders when it admitted California into the Union as a state. He argued further that even if these laws did not apply directly to this case, they should at least serve as evidence of Congressional intent regarding how similar cases should be decided going forward