Here we report direct physical evidence that confinement of molecular hydrogen (H
2
) in an optimized nanoporous carbon results in accumulation of hydrogen with characteristics commensurate with solid H
2
at temperatures up to 67 K above the liquid-vapor critical temperature of bulk H
2
. This extreme densification is attributed to confinement of H
2
molecules in the optimally sized micropores, and occurs at pressures as low as 0.02 MPa. The quantities of contained, solid-like H
2
increased with pressure and were directly evaluated using in situ inelastic neutron scattering and confirmed by analysis of gas sorption isotherms. The demonstration of the existence of solid-like H
2
challenges the existing assumption that supercritical hydrogen confined in nanopores has an upper limit of liquid H
2
density. Thus, this insight offers opportunities for the development of more accurate models for the evaluation and design of nanoporous materials for high capacity adsorptive hydrogen storage.