We report on the surface reconstructions of L1(0)-ordered MnGa (001) thin films grown by molecular beam epitaxy on a 50 nm Mn3N2 (001) layer freshly grown on a magnesium oxide (001) substrate. Scanning tunneling microscopy, Auger electron spectroscopy, and reflection high energy electron diffraction are combined with first-principles density functional theory calculations to determine the reconstructions of the L1(0)-ordered MnGa (001) surface. We find two lowest energy reconstructions of the MnGa (001) face: a 1 x 1 Ga-terminated structure and a 1 x 2 structure with a Mn replacing a Ga in the 1 x 1 Gaterminated surface. The 1 x 2 reconstruction forms a row structure along [100]. The manganese:gallium stoichiometry within the surface based on theoretical modeling is in good agreement with experiment. Magnetic moment calculations for the two lowest energy structures reveal important surface and bulk effects leading to oscillatory total magnetization for ultra-thin MnGa (001) films. (C) 2017 Elsevier B.V. All rights reserved.