Lamborn v. County Commissioners is a United States Supreme Court case that dealt with the issue of taxation. The case involved a dispute between the County Commissioners of Washington County, Maryland and the Lamborn family. The Lamborn family owned a large tract of land in the county and had been paying taxes on it for many years. In 1876, the County Commissioners passed a resolution that increased the tax rate on the Lamborn's land. The Lamborn family argued that the increase was unconstitutional and that they should not have to pay the higher rate. The Supreme Court ultimately sided with the Lamborn family, ruling that the County Commissioners had acted unconstitutionally in increasing the tax rate. The Court held that the Commissioners had exceeded their authority in raising the tax rate and that the Lamborn family was not obligated to pay the higher rate. The Court also held that the Commissioners had failed to provide the Lamborn family with due process of law, as they had not been given notice of the proposed increase or an opportunity to be heard. The decision in Lamborn v. County Commissioners established that local governments must provide due process of law when enacting tax increases. It also established that local governments must act within the scope of their authority when enacting tax increases, and that they cannot exceed their authority in doing so.

In Lamborn v. County Commissioners, the Supreme Court was tasked with determining whether a county commission had the authority to levy taxes on certain property owned by an individual in order to pay for public improvements. The majority opinion held that the commission did have such authority and could tax this particular property owner without violating his constitutional rights. However, Justice Field dissented from this ruling and argued that it violated both state law as well as due process of law under the Fourteenth Amendment of the United States Constitution. He noted that while states may grant counties some power over taxation, they cannot do so if it violates any other laws or constitutional provisions; in this case, he believed taxing one person's land for public improvement would be unconstitutional because it would constitute taking private property without just compensation or due process of law. Furthermore, he argued that even if there were no legal impediments to doing so, allowing counties to tax individuals' land for public works projects would create a dangerous precedent which could lead to arbitrary taxation practices across all levels of government.