In several applications at the Bureau of the Census and elsewhere, it is necessary to link an uncontrolled and perhaps garbled address on an input record with the controlled and standardized representation of that same address on a master file of possible addresses. For the Bureau of the Census, the linking permits the association of a numerical geographic code--which is present in the master file, but not on the input transaction record--and that geographic code then allows aggregation of other input data on the transaction record at county, city, and block levels. The assignment of these geographic codes to the input records is geocoding.