A number of factors can affect spatial associations among production areas for different crafts. Surprisingly, survey and excavation of craft production areas from the Harappan Phase (2600–1900 calibrated B.C.) at the Indus urban site of Harappa have revealed no evidence that production locations were related to control by nonproducers. Instead, the distributional groupings of craft production areas were at least partially related to similarities in manufacturing processes. The three craft categories were extractive-reductive crafts such as lithic- and shell-working, pyrotechnologically transformative crafts such as metal and pottery production, and bridging crafts like talc/steatite and faience production that have both reductive and high heating stages. The patterns of association may relate to knowledge relationships between the producers or to requirements of manufacturing. Other factors in production location may have been Harappan views of what constituted distinct crafts, the value of the goods produced, and the likely consumers. A further factor, hinted at by the location of production areas on the various mounds of Harappa, may have been Indus ideological beliefs about civic structure and the proper placement of manufacturing within city centers.