We present wavelengths and absolute intensities for 269 emission lines from a single active region observed by the Solar EUV Rocket Telescope and Spectrograph (SERTS) on 1989 May 5. For this catalog, the imaged spectra have been spatially averaged over a field of view 7"x276" cutting through the center of AR5464 at S18 W45. Wavelength coverage is 170-450A with a spectral resolution approaching 10,000. Most of the line positions are determined to 5mA or better, representing the highest accuracy yet obtained for solar wavelengths throughout this spectral interval. The relative photometric calibration of the instrument is good to +/-20% over its first-order range, and has been placed onto an absolute scale that should be correct to within a factor less than 2. Where known, identifications, atomic transitions and formation temperatures are also given. The identified lines arise from temperatures that cover the range 4.7<=logT<=6.8, providing information about the Sun's corona and upper transition region. Upper limits to the intensity of any emission line not included here can be estimated from the measured instrumental sensitivity. This averaged EUV spectrum should prove useful as a source of accurate wavelengths and intensities for emission characteristic of the high-temperature plasma associated with a solar active region and small subflare. Addresses: Thomas R.J. and Neupert W.M. Laboratory for Astronomy and Solar Physics, Code 680, NASA-Goddard Space Flight Center, Greenbelt, MD 20771