The Princeton University Superpipe, capable of generating Reynolds numbers from 31 × 103 to 35 × 106, has been used to study the effects of surface roughness on turbulence in fully developed turbulent pipe flow. Mean velocity and pressure gradient results, streamwise Reynolds stresses, and two point correlations have all been performed on flow through a commercial steel pipe, with krms/D = 1/26,000 = 38.5 × 10-6, where krms is the rms roughness height and D is the pipe diameter. The Reynolds number of these studies ranged from 76 × 103 to 20 × 106. It was found that through the transitionally rough flow regime, the friction factor behavior did not follow that predicted by the Colebrook correlation. In addition, when the flow moved into the transitional and fully rough flow regimes, the streamwise Reynolds normal stress in the outer layer was found to saturate at a maximum value and did not increase in the same manner as observed for smooth pipes.