The absorption spectrum of N2 that corresponds to excited states in the range 12.2 - 17.0 ev has been investigated at large dispersion. Data are presented for a very extensive Rydberg series of bands, which are interpreted and correlated with previous observations. The ionization potential of N2 corresponding to the series limit is 15.577 volts. Absorption beyond this point is complete for a path of ~0.5 mm atmos. From λ995 to λ815 the spectrum is well developed at ~0.2 mm atmos. Here most of the absorption is due to bands that show an open rotational structure which could usually be analyzed to give values of B'-B''. Several such bands above λ920 are correlated with the known states b and b'. In general the internuclear distance, re', was found to increase with energy, up to values 40 percent larger than for the normal state. Vibrational constants are unexpectedly small (ω'ω''<13), and the ratio ω'B' is about half the nearly constant value (Birge-Mecke rule) found for all the lower states of N2. There is some evidence that the coupling in a few of the more excited states represents a transition toward Hund's case d'.