Online Youth Mathematics Competition
The Online Youth Mathematics Competition is a student run competition for students 8th grade and under. The contest committee and problem writers are very experienced in problem writing (some having founded the "Holiday Problems" on the AoPS forums and one of those students being one of the founders of the OMMC). The contest difficulty ranges from the AMC 8 / Early MathCounts level all the way to advanced and late AIME level.
The contest is international although the majority of the students are from the USA. You can visit their website at http://oymcofficial.org/ for more information.
Currently, the contest also boasts a wide variety of prizes from AoPS gift cards to free private lessons from The Beauty Of Math. The 2021 Summer OYMC also included a special lecture / talk from TBOM.