National statistical agencies and offices collect information about a nation's population and institutions and make the information available to the public. Statistical agencies have the responsibility of designing data release strategies which will not violate pledges of confidentiality either through intent or neglect. When a statistical agency releases microdata products, one of the important considerations is the geographic detail on the file. The finer the geographic breakout, the greater the risk that a respondent may be identified based on individual or household characteristics. In this paper, we regard the number of population unique present on the microdata file as one of the components of a measure of disclosure risk and then relate this component of risk to identifiable geographic area size. One objective of this work is to contribute to the development of geographic area cut-offs when designing microdata release strategies.