The AMA Motocross Championship is a premier motocross racing series in the United States, organized by the American Motorcyclist Association. It features a series of outdoor races held on natural terrain tracks, where riders compete on high-performance dirt bikes. The championship typically runs from late spring to early fall, attracting top riders and teams from around the world. Races are divided into two main classes: 450 Class and 250 Class, based on the engine size of the motorcycles. Points are awarded based on finishing positions, and the rider with the most points at the end of the season is crowned the champion.