The MAR (Master Address Repository) was initiated, built and is maintained by DC GIS. DC GIS is the Washington, DC's Geographic Information System (GIS) Group which is part of the Office of the Chief Technology Officer (OCTO).
The Department of Consumer and Regulatory Affairs (DCRA) is the agency responsible for issuing new addresses. Applications for new addresses should be filed with DCRA. DC GIS assists DCRA in reviewing these address applications. Most of these addresses from the address application are then added to the MAR.