In the studies on ethnic immigrant groups in urban areas, the patterns of ethnic residential segregation have been central to geographical concerns, and many other important aspects such as the dynamic formation processes of ethnic territories and their changing structures relating to development of ethnic businesses and social organizations have tended to be overlooked by geographers. This paper is an attempt to understand the settlement processes of an ethnic group and the changing structure of its ethnic territory in an urban area, taking the example of Japanese immigrants and their descendants in Seattle, a city on the West Coast of the United States.In this paper, three aspects of the spatial processes of the ethnic group are considered: 1) population distribution, 2) spatial development of ethnic businesses, and 3) ethnic organizations and their facilities. To describe these changing aspects, the development history of the Seattle Japanese can be divided into five major stages; I (-1907), II (1907-1930), III (1930-1942), IV (1945-1955), and V (1955-).The main information for this study is based on the documents which the author collected during his research visits to Seattle from 1989 to 1993. From among many items, the Japanese-American directories of the years of 1916, 1928, 1936, 1949, 1967, 1973, 1983, and 1991 were examined to analyze the changing composition and distributional patterns of Japanese-owned or -managed businesses as well as their ethnic organizations and institutions. As for the changing population distribution of the Japanese, several existing studies by Miyamoto, Schmid et al., Leonetti, and Abe were helpful.In the first stage (-1907), the Japanese in Seattle, most of whom were young or middle aged single male labor migrants, lived mainly in the so-called‘skid road’area, the south fringe of downtown. A small number of pioneering business people ran restaurants, grocery stores, or hotels, mainly for local white laborers in the same area. However, few community facilities had been established by the end of this period and Japanese society had remained as a labor migrant society rather than changing to an ethnic community.In the second stage (1907-1930), the Japanese community in Seattle changed its character gradually over time with marriage and the coming of children as well as the establishment of social leadership and organizations, and became a true local ethnic community. Most of the Japanese in this period lived in a limited area on the south-west slope of the First Hill, and their community facilities such as churches, schools, and headquarters of various political, social, or economic organizations were located within this area. By the relatively early years of this stage, the Japanese began to run various kinds of businesses such as hotels, restaurants, groceries, barbershops, bathhouses, etc., and these commercial and business facilities were mainly concentrated in a small area of the western part of their residential core area. In this stage, a typical ethnic town of Japanese, the so-called Nihonjin-machi, or Japantown, appeared through the concentrations of their residences, business facilities, and social facilities into a small limited area in the urban region.In the third stage (1930-1942), new arrivals of Japanese immigrants ceased practically under the so-called Anti-Japanese Immigration Act which was passed in 1924, and the Japanese community suffered from the hostile atmosphere against Japanese of the host society. However, the proportion of the second-generation Japanese who were born in the United States was increasing rapidly and Japanese society reached a new mature stage owing to that generation growing up. The residential distribution of Japanese had generally retained the cluster pattern which was formed in the former stage, but some changes took place