Here in Ohio we are restricted to 18,000'. Out in the Nevada Black Rock desert we can go 300,000' My on-board video flight went around 3,000. You can't just go and fly these in your backyard either, need a FAA waiver. Up until a few years ago you needed to have federal explosives permit to possess the rocket motors, that law went away and they are easy to obtain now but you still need to be certified through 1 of 2 national organizations to purchase them.
If anyone or their kids is interested in high powered rocketry my office is on the Barberton/Akron border and you can stop by for the dime tour, have some cool stuff like 3 axis CNC, laser cutter, etc..