Under the 1790 U.S. Patent Act, a patent could last for no more than 14 years.
The Act did not automatically give every invention a uniform 14-year term. The first federal Patent Board—including Thomas Jefferson, Secretary of State Thomas Jefferson, Secretary of War Henry Knox, and Attorney General Edmund Randolph—decided whether an invention was sufficiently useful and important and assigned its term, subject to a maximum of 14 years.
The 1790 law was the first U.S. federal patent statute enacted under Congress’s constitutional authority. It covered useful arts, manufactures, engines, machines, devices, and improvements that were not previously known or used. Unlike later practice, applications were examined by senior government officials rather than by a permanent professional patent office.
Later laws changed both the length and method of calculating patent terms. The 1836 Act allowed a possible seven-year extension, while the 1861 Act established a 17-year term measured from grant. Modern U.S. patents generally last 20 years from the earliest effective filing date, so those current rules should not be applied retroactively to the 1790 Act.