Adams County v. Burlington & Missouri Railroad Co was a United States Supreme Court case that dealt with the issue of taxation. The case centered around the Burlington & Missouri Railroad Company, which had been granted a charter by the state of Iowa in 1853. The charter granted the company the right to construct and operate a railroad in the state. The company was also granted the right to purchase and hold real estate for the purpose of constructing and operating the railroad. In 1867, Adams County, Iowa, attempted to levy a tax on the company's real estate holdings. The company argued that the tax was unconstitutional, as it violated the terms of the charter granted by the state. The Supreme Court agreed with the company, ruling that the tax was unconstitutional. The Court held that the charter granted by the state was a contract between the state and the company, and that the state could not impose a tax on the company's real estate holdings without violating the terms of the contract. The Court also held that the tax was an unconstitutional burden on interstate commerce, as it would have a negative effect on the company's ability to operate its railroad.

Justice Field delivered the dissenting opinion in Adams County v. Burlington & Missouri Railroad Co, arguing that the majority had misinterpreted a provision of the Iowa Constitution and failed to recognize its full implications. He argued that while it was true that counties were not allowed to tax railroads for their property, this did not mean they could be exempted from taxes on income derived from such property. Justice Field noted that under Article 8 Section 1 of the Iowa Constitution, all real estate within a county must be taxed equally; thus he reasoned if one class of real estate is exempt from taxation then all other classes should also receive similar exemptions or else there would be an unequal application of taxation which violated both state and federal law. Furthermore, he argued that since railroad companies are corporations created by special acts passed by legislatures they should not enjoy any privileges beyond those granted to other citizens or organizations operating within a state's jurisdiction.