  The magnetic ground state and the crystalline electric field level scheme of
the triangular lattice antiferromagnet KCeO$_2$ are investigated. Below $T_N =$
300 mK, KCeO$_2$ develops signatures of magnetic order in specific heat
measurements and low energy inelastic neutron scattering data. Trivalent
Ce$^{3+}$ ions in the $D_{3d}$ local environment of this compound exhibit large
splittings among the lowest three $4f^1$ Kramers doublets defining for the free
ion the $J = 5/2$ sextet and a ground state doublet with dipole character,
consistent with recent theoretical predictions in M. S. Eldeeb et al. Phys.
Rev. Materials 4, 124001 (2020). An unexplained, additional local mode appears,
and potential origins of this anomalous mode are discussed.
