The one-electron density, and intracule (relative motion p = p1 - p2) and extracule [center of electron mass P = 1/2(p1 + p2)] pair densities for the first-row hydrides (LiH-FH) in their ground states have been calculated from both self-consistent-field (SCF) and configuration interaction (CI) wave functions. For each molecules, the anisotropic, radial, and projected one-electron and pair densities along (longitudinal) and perpendicular (transverse) to the molecular axis are displayed and analyzed. The moments of the one-electron and pair distributions in momentum space are also discussed. The effect of electron correlation on these momentum densities and moments have been studied.