Abraham Lincoln is perhaps America's most famous president, but few know that he was the only one to hold a patent. In 1849, Lincoln received a patent for designing a device meant to carry riverboats over shallow shoals. In his late teens and early twenties, Lincoln took several riverboat trips down the Ohio and Mississippi Rivers. Even when he was serving in Congress, Lincoln would sometimes travel between Washington and Illinois partway by riverboat. While on these journeys, he saw that there was room for improvement when it came to how these boats navigated treacherous waters.
On one such journey, Lincoln's boat became stranded on a sandbar. Everyone had to disembark and help work the boat back into deeper water. This sparked an idea in Lincoln's mind. He created a model of a device that could be fitted onto riverboats that would allow them to push themselves up and over shoals with the aid of adjustable buoyant air chambers.
While in Washington, Lincoln hired the services of an attorney and applied for a patent with the US Patent Office, which he received on May 22, 1849. However, his creative device was never actually built and used. The whole process of designing an invention and receiving a patent for it imparted in Lincoln great respect for patent law. Lincoln came to view patent law as one of the great motivators of American ingenuity.