HEO is an orbit significantly above the geostationary orbital line at approximately 35,786KM from sea level.

HEO is an orbit significantly above the geostationary orbital line at approximately 35,786KM from sea level. For a most distinct listing of the differences between Low Earth, Medium Earth and High Earth orbits, please refer to the following diagram: https://i.stack.imgur.com/BEUQD.jpg