Terahertz vibration -rotation -tunneling transitions have been measured between ca. 78.5 and 91.9 cm(-1), and assigned to A-E (ortho-para) combinations of NH3 monomer states. The spectrum is complicated by inversion splittings that correlate to E symmetry monomer rovibronic states. Twenty progressions have been assigned to six excited states involving an out-of-plane vibration and an in-plane intermolecular vibration. The quality of the fit was affected by strong Coriolis interactions among these states and possibly an additional K = 2 state that was not explicitly observed in the data.