An H{alpha} emission survey of the young cluster NGC 2264 in the Mon OB1 association resulted in the detection of 490 H{alpha} emission stars in a 25'x40' field approximately centered between the O7 V multiple star S Mon and the Cone Nebula. The survey was carried out with the wide-field grism spectrograph (WFGS) on the University of Hawaii 2.2m telescope on Mauna Kea. X-ray observations made with the European Photon Imaging Camera (EPIC) on board the European Space Agency's XMM-Newton satellite observatory will be discussed in a subsequent paper. Optical (BVR_C_I_C_) photometry was obtained for selected fields to supplement similar data from the literature. Spectra covering the 6000-8000{AA} region at a resolution of R~3000 (adequate for the determination of Li I {lambda}6708 line strengths) were obtained for 150 H{alpha} and X-ray emission sources with the Gemini Multi-Object Spectrograph (GMOS).

Cone search capability for table J/AJ/129/829/table1 (H{alpha} emission stars in NGC 2264)