Iron enriched in the isotope Fe57 has been incorporated into the surface of micron-sized γ-Fe2O3 particles in order to study the magnetic structure of the outermost cations. Mössbauer spectra in external longitudinal magnetic fields of 50 kOe establish that a non-collinear structure exists from 4.2 K to room temperature. Over this temperature range the canting angle, averaged over all cations, decreases by a factor of about two. The surface structure is discussed in terms of some possible models