Martinton v. Fairbanks is a United States Supreme Court case that was decided in 1884. The case involved a dispute between two parties over the ownership of a piece of land in the state of Illinois. The plaintiff, Martinton, claimed that he had purchased the land from the defendant, Fairbanks, in 1867. Fairbanks, however, argued that he had never sold the land to Martinton and that he still owned it. The Supreme Court ultimately sided with Martinton, ruling that he had acquired the land through a valid purchase. The Court found that Martinton had provided sufficient evidence to prove that he had purchased the land from Fairbanks, including a deed of conveyance and a receipt for the purchase price. The Court also noted that Fairbanks had failed to provide any evidence to support his claim that he had never sold the land. In its ruling, the Supreme Court held that Martinton had acquired a valid title to the land and that Fairbanks had no right to reclaim it. The Court also noted that Fairbanks had failed to take any action to challenge the validity of the sale within the time period prescribed by law. As a result, the Court affirmed the lower court's ruling in favor of Martinton.

In Martinton v. Fairbanks, the Supreme Court was tasked with deciding whether a contract between two parties could be enforced when it had been made without consideration and in violation of a state statute. The majority opinion held that the contract was not enforceable due to its lack of consideration and statutory violation. Justice Field dissented from this decision, arguing that while there may have been no actual consideration for the agreement, there were sufficient moral considerations present to make it binding on both parties. He argued that if one party had already performed their part of the agreement then they should be allowed to recover damages from any breach by another party as long as those damages are reasonable and justifiable under law. Furthermore, he argued that even though an act may violate a state statute or public policy does not necessarily mean it is void; rather such acts can still be enforced so long as they do not conflict with federal laws or constitutional rights.