In researching my ancestor, Thomas Johnson, Jr., two sources gave different answers to the question of where he lived in the District of Columbia. Looking through his probate papers, there seemed to be nothing on the sale of his house. There was an ad in the newpaper that his personal estate would be sold at his dwelling house on the 3d of April 1799 for cash, but no address was given.
The first of the two sources was a DAR paper giving genealogical information for Thomas Johnson Jr. In a paragraph describing his occupation:
In June 1795 he was appointed the first Postmaster of Washington and held office until his death. No building being provided, he established one at his residence, No. 175 (old number) Pennsylvania Avenue, between 17th and 18th Streets Northwest. This house was a few doors east of the headquarters of General Winfield Scott and remained in the possession of the family until after the death of Andrew Wallace Johnson.
The second source was a talk on the history of the Post Office read before the Columbia Historical Society, Washington, D.C., by Madison Davis on 12 May 1902. In the talk he mentions an old newspaper item:
The following public announcement of Mr. Johnson’s appointment to the office of postmaster, taken from the files of the Impartial Observer and Washington Advertiser of July 17, 1795 – an old newspaper whose existence has for a century been forgotten – is quite interesting as settling the hitherto disputed question as to the first location of the post-office – on the north side of F Street between 13th and 14th Streets N.W. – and as showing that the office actually began business – in July, 1795 – three months before the postmaster was commissioned, as shown by the records of the Post-Office Department.
Thomas Johnson Jr., 1753-1795
The map of Washington D.C. is from plate 23, Baist's Real Estate Atlas of Surveys of Washington, District of Columbia: complete in four volumes, by G. Wm. Baist, Philadelphia, 1909, and can be accessed at the Library of Congress, digital id http://hdl.loc.gov/loc.gmd/g3851bm.gct00133a.
Source for the DAR Records: "DAR Records from Lewellen Eliot, M.D in Supporting Documentation of Ella Baker Johnson (M332983) on Benjamin Johnson (A063019)," joined May 1942; National Society Daughters of the American Revolution, Genealogical Research System accessed November 20, 2017 DAR Library, Washington, D.C.
Source for the talk before the Columbia Historical Society: "A History of the City Post-Office," Records of the Columbia Historical Society, by Madison Davis, vol. 6, 1903, p.143-147.