An experimental investigation was conducted to study the effect of a surface protuberance on a compressible laminar boundary layer at Mach 6.48 and turbulent boundary layer at Mach 2. The surface heat transfer was studied upstream and downstream of a cylindrical protuberance using quantitative infrared thermography. The influence of the geometry of the cylinder on the surface heat transfer features is clarified for both the laminar and turbulent interactions. Furthermore, boundary layer transition is observed in the laminar interactions by identifying the turbulent wedge in the wake of the protuberance. A series of high and low heat transfer regions are observed in the wake of the protuberance in the turbulent boundary layer, indicating the presence of streamwise vortices.