An undermount sink and countertop combination is disclosed for use with a sink cabinet. The sink cabinet includes a sink-receiving opening and a sink cabinet width and depth. The sink includes a basin that is sized and shaped to be received within the sink-receiving opening. The basin includes side wall portions, an upper outer perimeter surrounding the side wall portions, and a bottom portion. A mounting flange extends from the upper outer perimeter of the basin. The mounting flange is shaped to rest atop the cabinet and underneath the countertop and is sized with a mounting flange width and depth substantially equal to the sink cabinet width and depth.