At the Chimu capital of Chan Chan, a Late Intermediate period (1000--1470 A.C.) urban site on the north coast of Peru, a series of coordinated studies is attempting to reconstruct the internal organization of the city and its relationships to rural sites in the vicinity. One of these studies has concentrated on a particular type of structure found throughout the capital and at several sites in the Moche, Chicama, and Viru Valleys. These structures are characterized by a unique U-shaped layout and are lined with niches, throught, or bins in their interior walls. Their distribution and location near important architectural features at Chan Chan follow a repetitive pattern that suggests that they played a key role in the administrative affairs of the city, serving as offices, control points, and places for the reception and re-distibution of goods. As such, these structures appear to be the seats of power for the administrators of the city. The occurrence of similar structures at rural sites in the vicinity provides an important link in the framework of urban-rural relationships in the region. This link substantiates evidence for a system of highly centralized control and authority of the agricultural and irrigation resoruces in the rural areas. Futhermore, an architectural seriation of U-shaped structures at Chan Chan has aided in setting up a sequence that traces the order of the construction of the monumental enclosures in the capital.