This work is an examination of those environmental and political factors which have influenced the distribution of settlement types in northwest Ireland during the Early Christian period (AD 500-1000). Various site types are discussed in Chapter One; the physical geography and history of the six counties of Northern Ireland which make up the study area is the subject of Chapters Two and Three. Cultural remains and written sources, both of which give insight into how society in general and the individual farm economies functioned during this period, are discussed in Chapter Four.