Proton accelerators producing beam powers of up to 1 MW are presently either operating or under construction and designs for Multi-Megawatt facilities are being developed. High beam power has applications in the production of high intensity secondary beams of neutrons, muons, kaons and neutrinos as well as in nuclear waste transmutation and accelerator-driven sub-critical reactors. Each of these applications has additional requirements on beam energy and duty cycle. This paper will review how present designs for future Multi-Megawatt facilities meet these requirements and will also review the experience with present high power facilities.