February 28 – The Baltimore and Ohio Railroad is incorporated, becoming the first railroad in America offering commercial transportation of both people and freight.
March 12 – In Brown v. Maryland, the United States Supreme Court ruled that imported goods in their original package are under federal jurisdiction and thus not subject to state regulation.
July 4 – Madawaska declares independence from the United States, as apart of a border dispute between British North America and the United States, so that it can be annexed by Maine.