Mount Pleasant v. Beckwith is a United States Supreme Court case that was decided in 1879. The case involved a dispute between the town of Mount Pleasant, Iowa and a man named Beckwith. Beckwith had purchased a piece of land from the town, but the town later attempted to reclaim the land. The town argued that the land was originally part of a larger tract of land that had been donated to the town by the federal government, and that the town had the right to reclaim the land. The Supreme Court ultimately sided with Beckwith, ruling that the town did not have the right to reclaim the land. The Court held that the town had no legal authority to reclaim the land, as the deed of conveyance from the federal government to the town did not include any provision for the town to reclaim the land. The Court also held that the town had no equitable right to reclaim the land, as the town had already accepted the deed of conveyance and had allowed Beckwith to purchase the land. In conclusion, the Supreme Court ruled in favor of Beckwith, holding that the town of Mount Pleasant did not have the legal or equitable right to reclaim the land that Beckwith had purchased.

In the case of Mount Pleasant v. Beckwith, the Supreme Court was asked to decide whether a tax imposed by an Iowa town on non-residents who worked there was constitutional. The majority opinion held that it was not unconstitutional as long as it did not discriminate against out-of-state workers and businesses. However, Justice Field dissented from this decision and argued that such taxation violated the Privileges and Immunities Clause of Article IV of the Constitution which states “The Citizens of each State shall be entitled to all Privileges and Immunities of Citizens in several States”. He reasoned that since citizens are taxed differently depending on their state or place residence, they should also be treated equally when working outside their home state regardless if they were residents or nonresidents; thus any taxes imposed upon them must be uniform across all states for both resident and nonresident alike. Furthermore, he argued that allowing towns to impose different taxes based on residency would create an unequal burden between those living within a particular jurisdiction versus those residing elsewhere - something which is prohibited under our federal system where every citizen has equal rights no matter what state they live in or work in.