Boechera pusilla is a perennial herb that occurs in the western United States, where it is endemic to Wyoming. It is restricted to the southern Wind River Range and known from a single population that is entirely on United States Bureau of Land Management lands. The species is not seriously impacted by threats in the present, but a lapse in management measures (exclosure becomes ineffectual) could reintroduce the threat of off road vehicles and grazing mammals. Future potential threats to this species include mining and energy development, climate change, and wildfires. Any of these could cause a rapid deterioration in the species' status, driving it to Critically Endangered or Extinct within a short timeframe. It is therefore assessed as Vulnerable D2.

Boechera pusilla occurs in the western United States, where it is endemic to Wyoming. It is restricted to the southern foothills of the Wind River Range (South Pass area) in Fremont County (Reeves 2017). This species is known from a single occurrence. Systematic surveys have not revealed any new occurrences.

In 2016, it was estimated that there were 1,669 plants (Reeves 2017). Population trends are not clear, as the survey methods have varied over the years and there have been new discoveries of sub-occurrences (Reeves 2017).

This species occurs in coarse soil that has accumulated in cracks and crevices of sparsely vegetated granite-pegmatite outcrops at about 2,350 m elevation. The surrounding plant community is sagebrush grassland. The habitat is exposed to high winds and extreme cold conditions with as few as 30 frost free days annually (Reeves 2017).
Boechera pusilla is apomictic, meaning it reproduces asexually without fertilization. Flowering seems to be related to climatic factors, with increased flowering in wetter years. Most seeds fall near the parent plant but some disperse by water and wind (Reeves 2017).

Grazing and motorized recreation impact are precluded by exclosures, provided they are maintained. As of 2017, energy and mineral extraction is a low level threat due to protections in place and current demands for resource extraction (Reeves 2017). The species' habitat is somewhat extreme, which makes it unfavourable for competitive and invasive species. However, climate change may make the habitat more favourable through less severe temperature and moisture conditions (Reeves 2017). Invasive species, like Bromus tectorum, occur in nearby areas and may contribute to an increased risk of wildfire into the future.

This species occurs in the Pine Creek Special Management Area (Bureau of Land Management) managed for fishing. It is also within an Area of Critical Environmental Concern (ACEC) which is managed for Boechera pusilla through measure including the construction of exclosures to prevent grazing livestock and motorized vehicle use. In addition, the occurrence is excluded from surface entry and mining until 2048 under under Public Land Order 7312 (BLM 1998).