Bryan v. Kennett, 113 U.S. 179 (1885), was a United States Supreme Court case in which the Court held that, under the treaty providing for the Louisiana Purchase, the United States would recognize property interests granted by the previous sovereign governments prior to the Purchase, even if the grant had been inchoate or incomplete.
The case involved a disputed title to land in the U.S. state of Missouri, which had previously been under the control of Spain and France before being acquired by the United States. In the late 1700s, the government of Spain had made a possibly incomplete grant of the land to a U.S. citizen, Moses Austin. Spain then lost control of the land to France in 1800, who in turn sold it to the United States. A question later arose as to whether Austin had received sufficient property rights from Spain to allow him to mortgage his land in 1818, or whether necessary rights had somehow passed back to the United States government, making the mortgage invalid and voiding subsequent land transfers that occurred pursuant to Austin's defaulting on the mortgage. Under the Court's holding, the incomplete grant to Austin was valid and sufficient to permit the mortgage.

Bryan v. Kennett is sometimes referenced as the Supreme Court's "ratification" of the Louisiana Purchase. However, the Court had already discussed and confirmed the legality of the Louisiana Purchase much earlier in American Insurance Co. v. Canter, 1 Peters (26 U.S.) 511 (1828).

Background
During the 1790s, Moses Austin, a former dry goods merchant who had married into an affluent iron mining family, had been one of the operators of a lead mine in southwestern Virginia and become known as the "Lead King". However, the business failed and Austin decided to leave the United States in order to avoid imprisonment for debt. He relocated to upper Spanish Louisiana, an area then controlled by Spain (which later became the U.S. state of Missouri), due to rich lead deposits in the region. Austin arranged with the Spanish government to receive a large tract of land in return for his swearing allegiance to the Spanish Crown and agreeing to settle some families in the area.

In 1797, the Spanish governor directed that Austin be placed in possession of land "one league square" (approximately 4,428 acres). Austin subsequently took possession of the land, moved his family onto it and built a house, blacksmith shop, and other improvements. In 1799, Spanish officials conducted a survey of the land and in 1802, the Spanish governor at New Orleans granted Austin the surveyed land. However, in the meantime Spain had returned Louisiana to France by operation of the Third Treaty of San Ildefonso in 1800, although Louisiana remained nominally under Spanish control until 1803, just before France sold it to the United States in the Louisiana Purchase. The land granted to Austin by the Spanish governor was therefore owned by France at the time of the 1802 grant and came under the jurisdiction of the United States in 1803.
Austin founded the Bank of St. Louis and was its principal stockholder. In 1818, he mortgaged his land to the bank for $15,000, but the bank failed in the Panic of 1819, causing Austin to lose his entire fortune and resulting in judgments being entered against him for approximately $14,500. Austin's land was subsequently seized and sold via sheriff's sale to pay his creditors. Following the sheriff's sale, Austin's land changed hands several more times and ended up in the possession of John Deane by 1835. However, Austin, perhaps in an effort to protect some of his assets, had also conveyed the land himself in 1820 to his son-in-law James Bryan and other grantees. Austin died in 1821, and Bryan in 1822.
In 1835, Deane brought a quiet title action in equity in Missouri against the heirs of James Bryan, who by then were living in Texas and failed to appear. Deane was awarded the right, title and interest to the land. Deane and his successors in title continued to occupy the land.





