  Employing \emph{VI} images of NGC 2419 acquired over 17 years, light curves
for most of the known variables in the field of the cluster are produced. A
cluster membership analysis for about 3100 stars in the cluster field with
proper motions from $Gaia$-DR3, revealed the presence of member stars as far as
140 pc from the cluster center and enabled the construction of a cleaner CMD
free of field stars. It was found that RRab and RRc stars share the inter-order
region in the instability strip, which is unusual for OoII clusters.
Theoretical considerations confirm that Pop II cepheids are descendants of
extreme ZAHB blue tail stars with very thin envelopes of about 10\% of the
total mass. Member RR Lyrae stars were employed to calculate independent
estimates of the mean cluster metallicity and distance; we found [Fe/H]$_{\rm
UV}= -1.90 \pm 0.27$ and $D=86.3 \pm 5.0$ kpc from the RRab and [Fe/H]$_{\rm
UV}= -1.88 \pm 0.30$ and $D=83.1 \pm 8.1$ kpc from the RRc light curves.
