To meet the challenging thermal requirements of modern power electronics, surface enhancements are being considered to improve the performance of single-phase microchannels. A simple modification of a surface dimplea two-dimensional grooveis considered due to its significant potential enhancement yet simple manufacture. A comprehensive series of simulations were performed to determine the optimal geometry and Reynolds numbers for thermal performance, which indicated that moderately deep features could result in nearly 75% greater average convective heat transfer coefficient with approximately 35% greater pressure penalty at turbulent conditions. This geometry promoted freestream separation at the leading edge, which resulted in downstream impingement and boundary layer development, producing an overall thermal benefit. This potential performance was demonstrated experimentally using a groove-enhanced minichannel design in a typical heat-sink application. Infrared thermography showed that deep grooves could indeed enhance the overall heat transfer coefficient of this module by the order of 20%, although shallower shapes had less impact.