A measurement of ground level muons was performed with the NMSU-WIZARD/CAPRICE magnet spectrometer in Fort Sumner, New Mexico, USA in Spring 1997. The spectrometer was equipped with a superconducting magnet, a time-of-flight system, an electromagnetic calorimeter and a Ring Imaging Cherenkov detector with a gaseous C_4 F_10 radiator. Positive and negative muon spectra and the mu^+ to mu^- ratio are presented in the momentum range from 200 MeV/c to 120 GeV/c. The results are compared with results obtained with a similar experiment at a different geomagnetic location. The data show latitude dependent geomagnetic effects.