Two data files which contain the 1980 Census of Population and Housing School District Equivalency Files, Master Reference Files (MARF) 3 and 4, are presented. These equivalency files were created by the Bureau of the Census using school district boundary maps. MARF 3 contains geographic items from census Summary Tape Files (STF) 1A and 3A as well as total population and housing counts. MARF 4 contains geographic items from census STFs 1B and 3B and total population and housing unit counts. The record count for MARF 3 is 382,058, and that for MARF 4 is 2,940,437. These files allow the user to prepare additional data summaries relevant to school districts and to relate administrative record summaries with census geographic data. TYPE OF SURVEY: National Survey; Census. POPULATION: All Persons and Housing Units in the United States. RESPONDENTS: Citizens of the United States. YEAR OF EARLIEST DATA: 1980. (SLD)