Hattie L Brown Realty, Inc. 1300 Mercantile Ln, Upper Marlboro, MD20774 Hattie L Brown Realty is located off MD-202 near the I-95 exit and Largo Town Center. There is a Fed-Ex and UPS drop…More box, plus a bus stop conveniently located outside the building. Hattie L Brown is a Certified Hud Broker and Member of Associations of Realtors. Some of the services that are available include property evaluation, property management and buyer brokerage. Licensed in Maryland, Virginia, and District of Columbia.