Northern Railroad v. The People was a landmark Supreme Court case that established the power of the federal government to regulate interstate commerce. The case arose when the state of Illinois attempted to impose a tax on the Northern Railroad Company, a railroad that operated in multiple states. The railroad argued that the tax was unconstitutional because it interfered with interstate commerce, which was the exclusive domain of the federal government. The Supreme Court agreed, ruling that the state tax was unconstitutional and that the federal government had the power to regulate interstate commerce. This ruling established the precedent that the federal government had the power to regulate interstate commerce, and it has been used to uphold numerous federal regulations since then.

In Northern Railroad v. The People, the Supreme Court was tasked with determining whether a state legislature had the power to tax railroads within its borders. The majority opinion held that it did not, as such taxation would be an unconstitutional interference with interstate commerce and thus beyond the scope of state authority. Justice Field dissented from this decision, arguing that states should have some control over railroad companies operating within their boundaries in order to protect public safety and welfare. He argued that while Congress has exclusive power over interstate commerce under Article I of the Constitution, states still retain certain powers related to internal affairs which include taxing businesses for revenue purposes or regulating them for health and safety reasons. Thus he concluded that states are entitled to impose taxes on railroads so long as they do not interfere with federal regulations or impede upon interstate commerce in any way.