Nickel coins are U.S. currency made primarily of nickel and copper. They are worth five cents and are commonly used in everyday transactions. The most recognized nickel coin is the Jefferson Nickel, which features a portrait of President Thomas Jefferson on the front and his home, Monticello, on the back. Nickels are part of the U.S. coinage system, which also includes pennies, dimes, and quarters. They are slightly larger than a dime but smaller than a quarter. The nickel has been in circulation since 1866 and has undergone various design changes over the years.