  A significant challenge in measurements of neutrino oscillations is
reconstructing the incoming neutrino energies. While modern fully-active
tracking calorimeters such as liquid argon time projection chambers in
principle allow the measurement of all final state particles above some
detection threshold, undetected neutrons remain a considerable source of
missing energy with little to no data constraining their production rates and
kinematics. We present the first demonstration of tagging neutrino-induced
neutrons in liquid argon time projection chambers using secondary protons
emitted from neutron-argon interactions in the MicroBooNE detector. We describe
the method developed to identify neutrino-induced neutrons and demonstrate its
performance using neutrons produced in muon-neutrino charged current
interactions. The method is validated using a small subset of MicroBooNE's
total dataset. The selection yields a sample with $60\%$ of selected tracks
corresponding to neutron-induced secondary protons.
