This study aims to investigate the major consequence of urban expansion in urban areas particularly in Debre Markos town with review of relevant literatures. The finding of the paper was presented by using charts, table, graphs, and figures. This study shows that Debre Markos town is one of Ethiopian urban settings experiencing unique rate of urbanization through expansion. The findings of the study showed that the trend of urban expansion increase from time to time mostly forest and cultivated land have been changed into different urban development uses such as residential, industrial, and commercial and other various institutions. The central factors that contribute to rapid expansion of the town are discussed with detail interpretation of the data. The adverse effects of rapid urban expansion on the natural (physical) environment due to land use change and in the town and nearby areas discussed in detail. Hence, the objective of this study was to assess the consequence of horizontal urban expansion on physical environment but for the future study it is necessary to focus on social and economic impacts.