Garrison v. Cass County was a United States Supreme Court case that dealt with the issue of taxation. The case involved a dispute between the plaintiff, William Garrison, and the defendant, Cass County, over the taxation of Garrison's property. Garrison argued that the county had illegally taxed his property, and he sought to have the taxes refunded. The Supreme Court ultimately ruled in favor of Garrison, finding that the county had acted unlawfully in taxing his property. The Court held that the county had failed to provide Garrison with proper notice of the tax assessment, and that the assessment was therefore invalid. The Court also held that the county had failed to provide Garrison with an opportunity to contest the assessment, and that the assessment was therefore also invalid. The Court's ruling established that taxpayers must be provided with proper notice and an opportunity to contest any tax assessment before it can be enforced.

In Garrison v. Cass County, the Supreme Court of the United States held that a county could not be sued without its consent. The case arose when William Garrison brought suit against Cass County in Minnesota for damages he had suffered as a result of an illegal tax assessment by the county. In his dissent, Justice Field argued that allowing counties to avoid liability through lack of consent would lead to injustice and unfairness because it would allow them to escape responsibility for their actions even if they were wrongfully done. He further argued that this was contrary to public policy and should not be allowed under any circumstances. Furthermore, he noted that there was no legal precedent or authority supporting such an exemption from liability and thus it should not be recognized by the court in this case either.