The T2K experiment is a long baseline neutrino oscillation experiment aiming to observe the appearance of { u} e in a { u}{mu} beam. The { u}{mu} beam is produced at the Japan Proton Accelerator Research Complex (J-PARC), observed with the 295 km dis
tant Super- Kamiokande Detector and monitored by a suite of near detectors at 280m from the proton target. The near detectors include a magnetized off-axis detector (ND280) which measures the un-oscillated neutrino flux and neutrino cross sections. The present paper describes the outermost component of ND280 which is a side muon range detector (SMRD) composed of scintillation counters with embedded wavelength shifting fibers and Multi-Pixel Photon Counter read-out. The components, performance and response of the SMRD are presented.
