Ohio has 3 classifications for each boys & girls but they deperately need to be revamped. The classifications are based on enrollment.
Divison I is the biggest schools and is for schools with ≥ 301 boys. For girls it's ≥ 305. There is a school in Ohio that has over 1300 boys and 1200 girls. They compete in the same division with the schools that have just a bit over 300 of each.
Division II is the middle division and is for 158-300 boys. For girls it is 163-304.
Division III is the smallest division and is for schools with ≤ 157 boys and ≤ 162 girls.
There really should be at least 4 divisons. The mega-schools, with attendance figures that are approaching 1000 of each sex or greater, should be in a division by themselves. The schools with attendance that hovers in the 300-500 range can rarely compete at the state meet with those schools. It's been talked about for years but the Ohio HS Athletic Association places little emphasis on cross. Football, meanwhile, has 7 divisions.
I'm not sure what the breakdown numbers are for T&F but they're similar. The state championship track meet is at Jesse Owens Track at Ohio State but there was a year or two that 3 different tracks were used. For those schools that had boys in one division and firls in the other division, it was an issue if each team had the same coach which is usually the case for HS track. Thankfully all meets are now back at Ohio State.
Other sports are sort of messed up also. Boys golf has 3 divisons but the girls only have 2. Soccer is 3 divisions for each gender and the smaller schools of D1 are at a huge disadvantage. Field hockey is just 1 division but there are probably less than 50 schools total that have teams. Basketball gets 4 divisions for each gender. Swimming and diving only get 2 divisions each. Softball & baseball each get 4 divisions.