Different kinds of dispersal behavior shown by stable fly, Stomoxys calcitrans (L.), populations in the southeastern United States are described. Adults tended to group at sites used by cattle. Flies emigrated from these groups in smaller numbers than indicated by trap results. Adults were spatially distributed according to sex, physiological age, and biological function. These distributions are difficult to observe, and results from previous studies have been confusing because of the interpretation of trap data. Short-distance dispersal of 5 km or more was documented at farm and beach locations. High-pressure areas in the Midwest and the western Gulf of Mexico caused northerly winds through northwest Florida, which resulted in long-distance dispersal of stable flies. Flies arrived on the beaches daily for as long as the winds were from the north. Long-distance dispersal is characterized by the sudden appearance of large numbers of flies on the beaches. Understanding dispersal mechanisms is important for the design of stable fly management and control programs.