Hardin, Administratrix, & Others v. Boyd, Administrator, & Others is a United States Supreme Court case that was decided in 1885. The case involved a dispute over the ownership of a slave named Eliza, who had been owned by a man named John Hardin. Hardin had died in 1864, and his will had stated that Eliza should be freed upon his death. However, Eliza was not freed until 1871, and in the intervening years she had been sold to a man named Boyd. The case was brought by Hardin's heirs, who argued that Eliza should be returned to them as Hardin's rightful property. The Supreme Court ultimately ruled in favor of Boyd, finding that Eliza had been legally sold to him and that Hardin's heirs had no legal claim to her. The Court reasoned that Hardin's will had not been legally enforced until 1871, and that Eliza had been legally sold to Boyd in the intervening years. The Court also noted that Hardin's heirs had not taken any action to enforce the will until after Eliza had been sold to Boyd. As a result, the Court held that Boyd was the rightful owner of Eliza and that Hardin's heirs had no legal claim to her.

In Hardin, Administratrix, & Others v. Boyd, Administrator, & Others (1885), the Supreme Court was tasked with determining whether a state court had jurisdiction to hear a case involving land located in two different states. The majority opinion held that the state court did not have jurisdiction over this matter and thus dismissed it. However, Justice Field dissented from this decision on the grounds that he believed that there were sufficient facts presented which would allow for an exercise of concurrent jurisdiction between both states involved in order to decide upon the dispute at hand. He argued that since each party had title claims within both states and those claims could be affected by either one's ruling alone then it should be allowed for them to join together in deciding upon these matters as they are related and intertwined with one another. Thus he concluded his dissent by stating "the parties having rights under laws of different States may unite their causes into one action."