We report new observations of the spectrum of singly ionized chromium (CrII) in the region 1142-3954{AA}. The spectra were recorded with the National Institute of Standards and Technology 10.7m normal-incidence vacuum spectrograph and FT700 vacuum ultraviolet Fourier transform spectrometer. More than 3600 lines are classified as transitions among 283 even and 368 odd levels. The new spectral data are used to re-optimize the energy levels, reducing their uncertainties by a typical factor of 20.