  Visible signals from the decays of light long-lived hidden sector particles
have been extensively searched for at beam dump, fixed-target, and collider
experiments. If such hidden sectors couple to the Standard Model through
mediators heavier than $\sim 10$ GeV, their production at low-energy
accelerators is kinematically suppressed, leaving open significant pockets of
viable parameter space. We investigate this scenario in models of inelastic
dark matter, which give rise to visible signals at various existing and
proposed LHC experiments, such as ATLAS, CMS, LHCb, CODEX-b, FASER, and
MATHUSLA. These experiments can leverage the large center of mass energy of the
LHC to produce GeV-scale dark matter from the decays of dark photons in the
cosmologically motivated mass range of $\sim 1-100$ GeV. We also provide a
detailed calculation of the radiative dark matter-nucleon/electron elastic
scattering cross section, which is relevant for estimating rates at direct
detection experiments.
