An offset header for attachment to a grain harvester includes a body having a back and a bottom which form a collection trough extending the length of the body. The back further defines at a first proximal and an opening for receiving and for attachment to a grain conveyor of a grain harvester. A mechanism is located at the bottom for removing and collecting a crop from an agricultural field, and a transfer mechanism is operationally positioned in the collection trough to transf's er the collected crop toward the opening. A drive unit at a second distal end of the body supports and propels the second distal end of the body in cooperation with a grain harvester.