  We employed the Skyrme-Hartree-Fock model to investigate the density
distributions and their dependence on nuclear shapes and isospins in the
superheavy mass region. Different Skyrme forces were used for the calculations
with a special comparison to the experimental data in $^{208}$Pb. The
ground-state deformations, nuclear radii, neutron skin thicknesses and
$\alpha$-decay energies were also calculated. Density distributions were
discussed with the calculations of single-particle wavefunctions and shell
fillings. Calculations show that deformations have considerable effects on the
density distributions, with a detailed discussion on the $^{292}$120 nucleus.
Earlier predictions of remarkably low central density are not supported when
deformation is allowed for.
