Auguste Chouteau's Heirs v. The United States was a Supreme Court case in which the heirs of Auguste Chouteau, a French settler who had been granted land by the Spanish government in 1794, argued that they were entitled to compensation from the US government for their loss when Congress annexed Missouri and took control of his property. The court ruled against them on two grounds: firstly, because it found that under international law at the time Spain did not have legal authority to grant title to lands within what would become US territory; secondly, because even if Spain had such authority it could only be exercised with respect to those lands actually occupied or improved by settlers prior to American acquisition. As Auguste Chouteau's claim was based solely on an unfulfilled promise made before any occupation or improvement occurred, he and his heirs were not entitled to compensation from the US government for its taking of their land.

In Auguste Chouteau's Heirs v. The United States, the Supreme Court was asked to decide whether a grant of land by the Spanish government in 1794 was valid and enforceable under U.S. law when it had been confirmed by Congress in 1804 but not patented until 1831. The majority opinion held that since no patent had been issued prior to the passage of the Act of 1804 confirming grants made before 1800, any such grant could not be enforced against subsequent purchasers from the United States or its officers acting on behalf of it as proprietor for lands within Missouri Territory after April 30th, 1803; thus affirming that title vested with those who purchased from them rather than with those claiming under an unpatented Spanish grant. In dissent however, Justice McLean argued that although there may have been some ambiguity regarding which party should prevail due to conflicting laws passed at different times concerning titles derived from Spain and France respectively, he believed that this case fell squarely within existing precedent established in previous cases involving similar facts where courts found for claimants based upon their possession and occupancy prior to April 30th ,1803 regardless if they were able to produce a patent or other evidence demonstrating title vesting during Spanish rule over Louisiana territory; therefore concluding that Chouteau’s heirs should be entitled to recover their property rights despite having failed previously obtain a patent for same prior thereto .