  We study the capability of the international linear collider (ILC) to probe
extra dimensions via the seesaw mechanism. In the scenario we study, heavy
Kaluza-Klein neutrinos generate tiny neutrino masses and, at the same time,
have sizable couplings to the standard-model particles. Consequently, a
Kaluza-Klein tower of heavy neutrinos (N) can be produced and studied at the
ILC through the process: e+e- -> vN followed by N -> Wl decay. We show that the
single lepton plus two-jets final states with large missing energy from this
signal process will provide a good opportunity to measure the masses and cross
sections of Kaluza-Klein neutrinos up to the third level. Furthermore, the
neutrino oscillation parameters can be extracted from the flavor dependence of
the lowest-mode signals, which give us information about the origin of
low-energy neutrino masses.
