Studies on terrestrial oxygen ion (O<sup>+</sup>) escape into the interplanetary space have considered a number of different escape paths. Recent observations however suggest a yet insufficiently investigated additional escape route for hot O<sup>+</sup>: along open magnetic field lines in the high altitude cusp and mantle. Here we present a statistical study on O<sup>+</sup> flux in the high-latitude dayside magnetosheath. The O<sup>+</sup> is generally seen relatively close to the magnetopause, consistent with observations of O<sup>+</sup> flowing primarily tangentially to the magnetopause. We estimate the total escape flux in this region to be ~ 7 × 10<sup>24</sup> s<sup>−1</sup>, implying this escape route to significantly contribute to the overall total O<sup>+</sup> loss into interplanetary space.