The authors report on the bottom-up fabrication and magnetic characterization of lateral MnAs nanowires (NWs) on partially SiO2-masked GaAs (1 1 1) B substrates by selective-area metal-organic vapor phase epitaxy (SA-MOVPE). Magnetic force microscopy reveals that multimagnetic domains are formed in the relatively long MnAs NWs with the length of 5 mu m or longer in the direction parallel to the NWs. In the relatively wide NWs with the width of about 0.6 mu m, multimagnetic domains are formed in the direction perpendicular to the MnAs NWs as well as in the direction parallel to the NWs. Multimagnetic domains change to a single magnetic domain with increasing the applied magnetic fields from 1000 to 2000 G. The magnetic domains are controllable by means of the NW shape and the applied magnetic fields in our NWs fabricated by SA-MOVPE. (C) 2014 Elsevier B.V. All rights reserved.