To study flame structure and extinction characteristics in low-stretch environments, a normal gravity low-stretch diffusion flame was established beneath a cylindrical PMMA sample of varying large radii. Burning rates, visible flame thickness, visible flame standoff distance, temperature profiles in the solid and gas, and radiative loss from the system were measured. A transition from the blowoff side of the flammability map to the quenching side of the flammability map was observed at approximately 6-7 s(-1), as determined by curvefits to the nonmonotonic trends in peak temperatures, solid and gas-phase temperature gradients, and nondimensional standoff distances. A surface energy balance reveals that the fraction of heat transfer from the flame that is lost to in-depth conduction and surface radiation increases with decreasing stretch until quenching extinction is observed. This is primarily due to decreased heat transfer from the flame, while the magnitude of the losses remains the same. A unique local extinction flamelet phenomenon and associated preextinction oscillations are observed at very low stretch. An ultimate quenching extinction limit is found at low stretch with sufficiently high induced heat losses.