Race bridging refers to making data collected using one set of race categories consistent with data collected using a different set of race categories, to permit estimation and comparison of race-specific statistics at a point in time or over time. More specifically, race bridging is a method used to make multiple-race and single-race data collection systems sufficiently comparable with permit estimation and analysis of race-specific statistics such as birth and death rates. This entry provides an overview of the origins of race bridging and race-bridging methods and focuses on race bridging to estimate single-race population counts, as this has been the primary use of race bridging to date.