US Lacrosse establishes eligibility guidelines in order to promote the game of lacrosse among the youth of America in a safe and sportsmanlike environment. To best achieve this goal, US Lacrosse believes that leagues, associations, and other organizers of youth lacrosse should seek to provide playing opportunities that, as much as possible, establish a "level playing field" among players of similar age, size, and ability. 

Teams participating in NHYLA will be based on grade level first, providing that current age eligibility requirements are met. Grade levels are defined as follows:

12U - 6th and 5th grades. In addition, all players must be 12 years old or younger on the August 31st preceding competition.

10U - 4th and 3rd grades. In addition, all players must be 10 years old or younger on the August 31st preceding competition.

8U - 2nd and 1st grades. In addition, all players must be 8 years old or younger on the August 31st preceding competition.