A toilet seat apparatus for use outdoors includes a toilet seat and a clamp assembly attached to the toilet seat via hinges. The clamp assembly includes two jaw members for exerting a compressive clamping force on a tree to support the toilet seat above the ground. The clamp assembly also includes a drive mechanism to control the distance between the two jaw members and the clamping force. The major components of the clamp assembly are coplanar with one another so that when the clamp assembly is rotated about the hinges, the dimensions of the toilet seat apparatus are substantially minimized.