Three hypotheses are examined to account for trade linkages among communities. On the basis of ecological models of urban systems, position in the metropolitan hierarchy, functional specialization, and accessibility to early interregional trade routes are hypothesized to be important for current trade relations. The degree of trade is operationalized for each of 68 southern BEAs through the use of national data on inter-area commodity exchange. A trade index is constructed from these data which summarizes the volume of shipments/receipts, the range of products shipped/received, and the number of trading partners (product origin/destination communities) for each BEA. Bivariate analysis suggests that trade is related as expected with each community characteristic. However, differences in trade among communities with varying functional specializations become insignificant when the other constructs are controlled.