District of Columbia Land and Property
When Maryland and Virginia ceeded portions of their land to create the District of Columbia, they kept original records for that early time period in their respective counties. Deed books for Alexandria County, Virginia, (now Arlington County) are at the Alexandria City courthouse. FHL Collection, deeds (1783-1865) start with film 30170; index (1793-1870), films 30168-69. The Family History Library also has the Maryland Circuit Court deeds for Prince George's County (FHL Collection, index (1696-1884) films 14277& 14278, deeds start with film 14247) and Montgomery County (FHL Collection, index (1773-1863) film 14207; deeds start with film 14208).
A list of the earliest settlers is in Bessie Wilmarth Gahn, Original Patentees of Land at Washington Prior to 1700 (1936 reprint; Baltimore: Genealogical Publ., 1969) FHL Collection, book 975.3 R21g; located also at these libraries.