Williams v. Conger is a United States Supreme Court case that was decided in 1889. The case involved a dispute between two parties over the ownership of a piece of land in the state of Iowa. The plaintiff, Williams, claimed that he had purchased the land from the defendant, Conger, in 1876. Conger, however, argued that he had never sold the land to Williams and that he was still the rightful owner. The Supreme Court ultimately sided with Williams, ruling that he had acquired the land through a valid purchase. The Court found that Conger had made a verbal agreement to sell the land to Williams and that Williams had paid the agreed-upon price. The Court also found that Williams had taken possession of the land and had made improvements to it, which further established his ownership. The Court's decision in Williams v. Conger established that verbal agreements can be legally binding and that a purchaser can acquire title to land through such an agreement. The case also established that a purchaser can acquire title to land through possession and improvements, even if there is no written agreement.

Justice Field delivered the dissenting opinion in Williams v. Conger, arguing that a state court's decision should not be overturned by the Supreme Court unless it is "clearly wrong." He argued that there was no such clear error in this case and thus the judgment of the lower court should stand. The dispute arose from an agreement between two parties to exchange land; one party later claimed they had been defrauded and sought relief from a state court. Justice Field noted that while some evidence suggested fraud may have occurred, other evidence indicated otherwise. In his view, since both sides presented plausible arguments as to why their interpretation of events was correct, it would be inappropriate for him or any other justice to overturn the ruling of a competent state tribunal which had heard all relevant testimony and weighed all available facts before making its decision.