Abraham Alfonse Albert Gallatin (January 29, 1761 – August 12, 1849) was a Swiss-American ethnologist, linguist, politician, diplomat, congressman, and the longest-serving United States Secretary of the Treasury. In 1831, he founded the University of the City of New York. In 1896, this university was renamed New York University; it is now one of the largest private, non-profit universities in the United States.

Born in Switzerland, Gallatin immigrated to America in the 1780s, ultimately settling in Pennsylvania. He was politically active against the Federalist Party program, and was elected to the United States Senate in 1793, but was removed from office by a 14–12 party-line vote after a protest raised by his opponents suggested he had fewer than the required nine years of citizenship. In 1795 he was elected to the House of Representatives and served in the fourth through sixth Congresses, becoming House Majority Leader. He was an important leader of the new Democratic-Republican Party, its chief spokesman on financial matters, and led opposition to many of the policy proposals of Treasury Secretary Alexander Hamilton. He also helped found the House Committee on Finance (later the Ways and Means Committee) and often engineered withholding of finances by the House as a method of overriding executive actions to which he objected. While Treasury Secretary, his services to his country were honored in 1805 when Meriwether Lewis named one of the three headwaters of the Missouri River after Gallatin.