Introduction: The High Resolution Imaging Science Experiment (HiRISE) flying on the Mars Reconnaissance Orbiter (MRO) since 2005, is returning the highest resolution orbital imagery of Mars to date (up to 25 cm pixel scale). HiRISE acquires stereo images by rolling MRO off-nadir on two different orbits to reimage a target under as similar lighting conditions as possible. Digital Terrain Models (DTMs) can be derived from such stereo that have a vertical precision of better than 25 cm, given a stereo convergence angle of 20o and unbinned source images [1]. HiRISE DTMs created at the U.S. Geological Survey Astrogeology Science Center and the University of Arizona Lunar and Planetary Lab, HiRISE Operations Center (HiROC), were released to the NASA Planetary Data System (PDS) for the f i r s t t ime in 2010 a t http://hirise.lpl.arizona.edu/dtm/. Prioritization and Timeline for PDS Release: Over 1900 stereo pairs have been acquired since HiRISE arrived in orbit around Mars in 2006. However, due to the intensive resources required to create terrain models, only ~100 DTMs have been produced so far. Not all DTMs produced by participating institutions will be released to the PDS. DTMs produced by the HiRISE team are released to the PDS one year from the date of completion. Exceptions to this policy are DTMs produced for contracted landing site studies (e.g. Phoenix Lander, MSL) which are released almost immediately. Method: A HiRISE DTM is a gridded (raster) terrain model, constructed from two HiRISE stereo images as described in [2]. HiRISE is a pushbroom camera, with a focal plane array of 14 CCDs (10 panchromatic, or RED, across the full swath width), arranged to provide horizontally and vertically overlapping image strips [1]. Source data are taken from the stage in the HiROC downlink and image processing system that have been radiometrically and geometrically calibrated. The RED CCDs are processed with the ISIS 3 http://isis.astrogeology.usgs.gov/) application noproj which removes camera distortions and CCD offsets, and mosaics the 10 RED CCDs (full swath width). The mosaicked images are brought into the photogrammetry software SOCET SET (© BAE Systems, Inc.). In SOCET SET, the images are triangulated and registered to MOLA profiles [3]. Most HiRISE projects can be triangulated successfully to a solution with < 0.7 image pixels total RMS error. The images are then pairwise rectified, to put them in epipolar space. Automated terrain extraction algorithms in SOCET SET generate a terrain model at the specified post spacing. The model is edited for major blunders or artifacts if possible. Manual editing is extremely time consuming so major effort is put into making the input and solution as good as possible to minimize processing artifacts. The source images are then orthorectified to the DTM, at the same scale as the DTM, and at the full resolution of the original images. The output from SOCET SET is map projected.