Individual OH(v,N) rotational state population column densities have been derived from spectral analysis of CIRRIS 1A nighttime earthlimb airglow data. Both pure rotation and vibration-rotation fundamental sepctra have been examined, providing unique information on highly excited rotational states of OH(v=0--6). The relative populations of the four spin sublevels have also been determined. These findings provided important insights into OH dynamics at the mesopause. ¿American Geophysical Union 1993