San Juan Red ware pottery was distributed across the northern Southwest from the eighth through tenth centuries A.D., though made only in the northern San Juan region. This paper investigates the concentration (Costin 1991) of San Juan Red ware production through neutron activation analysis of the pottery and raw materials. Production was concentrated in the area of southeast Utah, and within that area it appears to have been produced at only a limited number of sources, possibly by specialized pottery-making communities. These results have implications regarding economic organization, exchange, and mobility.