We measure the Seebeck coefficient S in large arrays of lightly doped n-Si nanowires (SiNWs). Our samples consist of ~10^7 NWs in parallel, forming a “bulk” nano-structured material. We find that the phonon drag component of S, a manifestation of electron-phonon scattering in the sample, is heavily suppressed due to surface scattering, and that there is a “universal” temperature dependence for S. Furthermore, at room temperature, S is enhanced in the arrays by up to ~3 times in comparison to bulk Si.