This brown-bodied dragonfly varies from 1.8 to 2.2 inches in length. There are a few dots on front edges of the wings with brown-edged veins, but hindwings have large amber spots at the base. There is little pattern on the body, and yellowish lateral stripes on the abdomen. The sides of the thorax are lighter than the front. The eyes are brownish green. The abdomen may become blackish with age. Like the smoky shadowdragon, the stygian shadowdragon tends to fly over water during the last hour before darkness, most intensely in the last half hour. Populations of Neurocordulia are therefore most easily found by searching appropriate habitats for exuviae during June and July.
Common throughout eastern United States, from Tennessee to Maine, the stygian shadowdragon prefers clean lakes and large rivers with water in constant motion and not too acid. It is occasionally found throughout Wisconsin in larger rivers.
Throughout its range, the typical flight season is from mid-May to early August.