  We study the LHC sensitivity to probe a long-lived heavy neutrino $N$ in the
context of $Z'$ models. We focus on displaced vertex signatures of $N$ when
pair produced via a $Z'$, decaying to leptons and jets inside the inner
trackers of the LHC experiments. We explore the LHC reach with current
long-lived particle search strategies for either one or two displaced vertices
in association with hadronic tracks or jets. We focus on two well-motivated
models, namely, the minimal $U(1)_{B-L}$ scenario and its $U(1)_{X}$ extension.
We find that searches for at least one displaced vertex can cover a significant
portion of the parameter space, with light-heavy neutrino mixings as low as
$|V_{lN}|^2\approx 10^{-17}$, and $l=e,\mu$ accessible across GeV scale heavy
neutrino masses.
