Who was the shortest president of the United States?

The smallest U.S. President was James Madison. The fourth President, Madison stood 5 feet, 4 inches (163 centimeters) tall and weighed less than 100 pounds (45 kilograms).

James Madison, Jr., (March 16, 1751 – June 28, 1836) was an American statesman and Founding Father who served as the fourth President of the United States from 1809 to 1817. He is hailed as the "Father of the Constitution" for his pivotal role in drafting and promoting the United States Constitution and the Bill of Rights.

As Jefferson's Secretary of State (1801–1809), Madison supervised the Louisiana Purchase, which doubled the nation's size. Madison succeeded Jefferson as president in 1809, was re-elected in 1813, and presided over renewed prosperity for several years. After the failure of diplomatic protests and a trade embargo against the United Kingdom, he led the U.S. into the War of 1812. The war was an administrative morass, as the United States had neither a strong army nor financial system. As a result, Madison afterward supported a stronger national government and military, as well as the national bank, which he had long opposed.