Under the very general topic of an historical or temporal central place study, one particular approach to analyzing the centrality of urban places is outlined. Centrality is taken in a very limited context - the influence of an urban place over its umland. The relationship between population of an urban place and number of "labour units", or central labour units, is used to measure the relative centrality for a sample of places. "Labour units" themselves are introduced to denote all persons working in central activities in an urban place. The study is carried out in Kent and Lambton counties in Southwestern Ontario using data obtained from the available national, provincial and county directories. Rather than limit the study to one point in time, as most earlier works have, an analysis is carried out through time, from 1851 to 1857. Small urban places are the focus of attention in this study because of data availability and accuracy. Results show a noticeable decline in centrality over time, which is more marked in the later years. General trends are also drawn for changes in centrality in individual towns of differing and similar sizes. Some of the problems and shortcomings of the study are outlined as a guide to further research. / Thesis / Master of Arts (MA)