Junior hockey is a level of competitive ice hockey generally for players between 16 and 21 years of age. Junior hockey leagues in the United States and Canada are considered amateur (with some exceptions) and operate within regions of each country. In the United States, the top level is Tier I, represented by the United States Hockey League. Tier II is represented by the North American Hockey League. There are several Tier III and independently sanctioned leagues throughout the country. A limited number of teams in the Canadian major junior leagues are also based in the United States.