Camp Half Blood is a place near long island sound. Where the children of greek gods like, Zeus Hades and Posiedon, Live so that they wont be atacked by monster such as ,The Hydra, a three head monster that grows back the heads that are chopped of times two. The People there are Demigods and Satyrs there are also dryads and nymphs. this place and Camp Jupiter are apart of Rick Roirdans series of books. Percy Jackson and the Olympians and The Heros Of Olympus series. here is the link to go to the wiki