On the Alcator C-Mod tokamak [Phys. Plasmas 1, 1511, (1994)], radial profiles of electron temperature (T_e) and density (n_e) are measured at the plasma edge with millimeter resolution Thomson scattering [Rev. Sci. Instrum. 72, 1107 (2001)]. Edge transport barriers in the high confinement regime (H-mode) exhibit T_e, n_e pedestals with typical widths of 2-6 mm, with the T_e pedestal on average slightly wider than and inside the n_e pedestal. Measurements at both the top and the base of the pedestal are consistent with profiles obtained using other diagnostics. The two primary H-mode regimes on C-Mod, enhanced D_a (EDA) and edge-localized mode free (ELM-free), have been examined for differences in pedestals. EDA operation is favored by high edge collisionality n^*, in addition to high edge safety factor q₉₅. Scaling studies at fixed shape yield little systematic variation of pedestal widths with plasma parameters, though higher triangularity is seen to increase the n_e pedestal width dramatically. Pedestal heights and gradients show the clearest dependencies on plasma control parameters. Pedestal n_e and T_e both scale linearly with plasma current I_P, while pedestal T_e depends strongly on power flowing from the core plasma into the scrape-off layer P_SOL. The electron pressure (p_e) pedestal and p_e gradient both scale with I_P² P_SOL^1/2. Plasma stored energy W_P scales with pedestal p_e, implying that pedestal scalings may in large part determine global confinement scalings. 

KEYWORDS: H-modes; Pedestal; Scaling laws; Alcator C-Mod; Enhanced D-alpha