According to the United States Constitution, a presidential candidate must be at least 35 years old. There is no upper age limit. In addition to minimum age, presidential hopefuls must fulfill other requirements.
Presidential candidates must be natural-born citizens of the United States. This does not necessarily mean that they must have been born in any of the 50 states. John McCain, a 2008 presidential candidate, was born in 1936 of American parents in the Panama Canal Zone, which was under American control at the time. In addition to being natural-born, a candidate must have been a resident of the United States for at least 14 years.