We investigate the pair-production of right-handed neutrinos via the
Standard Model (SM) Higgs boson in a gauged $B-L$ model. The
right-handed neutrinos with a mass of few tens of GeV generating
viable light neutrino masses via the seesaw mechanism naturally
exhibit displaced vertices and distinctive signatures at the LHC. We focus on the displaced leptonic final
states arising from decays of the SM Higgs, and analyze the sensitivity
reach of the LHC and its beyond in probing the
active-sterile neutrino mixing. We also analyse pair production of right-handed neutrinos from the
decay of the additional neutral gauge boson $Z^\prime$. This is interesting
especially when $Z^\prime$ is relatively light which can lead to displaced
vertices in the forward direction. We perform a similar simulation
focused on displaced final states at FASER 2, MAPP*, CODEX-b and LHCb and MATHUSLA, CMS detectors for such a
process.