We propose a MuSR study of the magnetism in Mn-doped ZnGeP2 during this round of experiments using muon spin depolarization measurements in a longitudinal magnetic field. This material is one of several chalcopyrite-structured II-IV-V2 compounds that reportedly show ferromagnetic order above 300 K when doped with Mn, and are therefore being investigated for possible spintronics applications. We expect to be able to determine whether the FM order occurs throughout the whole sample or may be due to inclusions of an FM impurity phase. This particular material has an AFM ground state, thus we plan to also investigate the FM to AFM transition reported below 50 K. Our previous MuSR studies of ZnGeP2 have shown that the positive muon is most likely not diffusively mobile below 400 K, therefore the muon should be an excellent stationary probe of the local magnetism in this material.