Found only near South Pass City south of the Wind River Range in Fremont County, Wyoming, Fremont County rockcress occupies sparsely vegetated, coarse granite soil pockets in exposed granite-pegmatite outcrops, with slopes generally less than 10 degrees, at an elevation between 8,000 to 8,100 feet (Dorn 1990, pp. 3, 6). A pegmatite is a very coarse-grained igneous (formed from magma or lava) rock that usually occurs in dikes (sheet-like bodies of magma) (Heidel 2005, p. 8). The soils are sandy to loamy (mixture of clay, silt and sand), poorly developed, very shallow and possibly subirrigated by runoff from the adjacent exposed bedrock (solid consolidated rock) (Dorn 1990, pp. 6–8). Fremont County rockcress is likely restricted in distribution by the limited occurrence of pegmatite in the area (Heidel 2005, p. 8), though there is a possibility that the species may be more far-ranging based on the distribution of its parent species and the concept of geographical parthenogenesis (where apomictic species have wider distributions than their sexual relatives; Hörandl 2009 p. 161).

The single known occurrence lies on approximately 18 acres of habitat. A distribution model shows that potential habitat could occur across an area no greater than two townships (186.5 square kilometers) (Heidel 2005, p. 7), and a more recent model predicts that this species will be found nowhere else in the state (Andersen et al. 2016, Appendix 2, pp. 151-154), though there is potential for additional occurrences in nearby areas that have not been surveyed. However, much of the surrounding area that is administered by the Rock Springs Field Office of the BLM has been surveyed for this species and no other occurrences have been found to date. In 2016 and 2017, a new occurrence and an expansion of the first occurrence were thought to be discovered, respectively; however, these plants were determined to be a different species than Fremont County rockcress. The dense nature of pegmatite combined with the persistent, strong winds, does not allow for fertile soil formation, and therefore restricts vegetation growth (Heidel 2005, p. 15). The specialized habitat requirements of Fremont County rockcress have allowed the plant to persist without competition from other herbaceous plants or sagebrush sagebrush
The western United States’ sagebrush country encompasses over 175 million acres of public and private lands. The sagebrush landscape provides many benefits to our rural economies and communities, and it serves as crucial habitat for a diversity of wildlife, including the iconic greater sage-grouse and over 350 other species.

Learn more about sagebrush -grassland species that are present in the surrounding landscape (Dorn 1990, pp. 6, 8), though no specific studies have been conducted to determine the exact values of these specialized habitat parameters.