The first settlements in Rio Arriba County, New Mexico, were the 14th century Tewa Indian Pueblos, autonomous socio-economic units based on agriculture. Similar Hispano villages were founded by colonists beginning in the late 16th century and continuing to the early 19th century, when the Chama Valley was used increasingly as a trade route. After the 1848 Treaty of Guadalupe Hidalgo, Anglo settlers (cattlemen, railroad employees, miners) arrived in the area and completed the tri-cultural makeup of the county. Each culture contributed to the county's ideas of political, social, and economic community linkages. During the early 20th century, the traditional Indian and Hispanic village pattern began to evolve into a settlement hierarchy; Chama and Espanola evolved as the county's dominant towns. Although the towns were new, they were both associated with the railroad which guaranteed a trade advantage. The shift to highway transportation helped establish Espanola as the county's leading trade center and largest town. Like Chama and Dulce, somewhat smaller communities, Espanola was originated by Anglo settlers in the late 19th century. Completing the settlement hierarchy are the Indian and Hispanic villages which have remained very small and provide few community services besides elementary schooling. (Author/SB)