Technical Abstract: Residues at sites where stationary feeders have been used to provide hay as supplemental forage for cattle during the winter are developmental substrates for immature stable flies, Stomoxys calcitrans (L.), in the central United States. Winter hay feeding sites normally have a circular footprint with residues extending 3-7 m from the feeder. Spatial patterns in physical (substrate depth, temperature, water content), chemical (pH, electrical conductivity, total nitrogen [N] and carbon [C], ammoniacal nitrogen [NH4-N], and extractable phosphorus [P]), and biological (microbial respiration rate) substrate properties for two feeding sites were estimated and the correlations between these properties and adult emergence were characterized. With the exception of extractable P all substrate properties exhibited spatial patterns centered on the feeder location. Adult stable fly emergence was correlated with substrate pH (R2 = 0.58), moisture content (R2 = 0.58), EC (R2 = 0.59), NH4-N concentration (R2 = 0.72), total N concentration (R2 = 0.46), total C concentration (R2 = 0.59), and microbial respiration rate (R2 = 0.81). Better understanding physical, chemical, and biological conditions needed for larval development may help in identifying additional developmental habitats and management of this pest. Targeted implementation of management practices such as sanitation practices and chemical treatments can be applied to smaller areas reducing labor input and improving cost effectiveness.