This paper describes the design and evaluation of a new system for training terrain visualization. Visualizing the military aspects of terrain is an important but difficult skill to train and acquire. More traditional approaches to training terrain visualization rely heavily on field-based and paper-based training that severely constrain the terrain locations and formats available. Recognition of this prompted the U.S. Army to award a Small Business Technology Transfer (STTR) contract to combine training theory and technology to improve terrain visualization training. The prototype training system developed A²TV (Anytime, Anywhere Terrain Visualization Training), allows trainees to interactively view and vary digital representations of terrain by flying and driving through terrain, morphing terrain, and overlaying contour information. The hypothesized value of the A²TV is its ability to harness the potential of interactive training formats with proven training methods including consistent conditions, multiple trials, and immediate feedback. We developed a set of structured exercises in both open and urban terrain areas to train basic skills like visualizing landforms, as well as tactical skills, like identifying key terrain and determining avenues of approach. An evaluation of training with the A²TV compared the landform visualization performance of three groups of civilian students (n= 51) by training format: Fly-/Drive-Thru, Terrain Morph, and Contour Overlay. Our results from the training evaluation demonstrate that two of the training methods result in significant improvement. In addition, we conducted a training potential and usability evaluation with active duty military personnel (n= 30) to refine the A²TV for future training and evaluation efforts. The military participants affirmed the need for training for terrain visualization, provided many constructive recommendations for A²TV refinement, and acclaimed the potential of the A²TV system for training as well as mission planning and support.