For several years after the founding of Georgetown, there were no buildings to the north of what is now M Street. By 1789, however, the year when Georgetown was incorporated, much of the the northwest portion of the Town, and even some areas beyond, was well populated, with a complete grid of north / south and east / west streets. In those days, however, 34th Street was called Frederick Street, 35th Street was Fayette Street, and N Street was First Street. Prospect Street, though, has always been so named, taking its name from Benjamin Stoddert, the first owner of Halcyon House, who called his estate there "Pretty Prospect.")
The rare map reproduced below shows not only the location of many of the first streets of Georgetown in 1799, but also the particular buildings then existing. On this map there can be seen a cluster of buildings across Prospect Street from where the Fraternity House now stands. All were part of the Benjamin Stoddert "Pretty Prospect" estate and surrounded his home "Halcyon House," the grand edifice which still exists on the southwestern corner of 34th and Prospect and faces the present Delta Phi Epsilon House. No buildings at that time, however, existed on the north side of Prospect, other than those few seen a block to the west, grouped near John Thomson Mason's home (later called "Quality Hill") at the corner of what is now 35th and Prospect.
One interesting detail on this map is that in 1799 Prospect Street had not yet been extended all the way east to what is now Wisconsin Avenue, but went eastwards only to what is now 34th Street.
The area making up the Town of Georgetown grew by a series of "Additions." Show below is a modern map that identifies each of the various Additions for the western half of Georgetown. From this map we can see that the Fraternity House was built on land that was in the original Town of Georgetown, while the apartment building to the immediate west of the Fraternity House was built in the "Peter, Beatty, Threlkeld & Deakins Addition."
In 1790 the State of Maryland ceded Georgetown, along with a large part of its Montgomery and Prince Georges Counties, to the United States as part of its donation of land for the new Federal Territory that came to be known as the District of Columbia. The District's earliest land records for Georgetown, therefore, continued the Maryland real estate denominations. The site of the Fraternity House was then simply "Lot 31 of Square 51 of Georgetown." The Town of Georgetown continued for years as a distinct municipality within the Distrct of Columbia, indepedent of the City of Washington". Later, when in 1880 the City of Washington annexed Georgetown, "Square 51 of Georgetown" was re-designated as "Square 1221 of Washington". And then, some years, later that "Lot 31 of Square 1221" was re-designated as "Lot 85 of Square 1221". Lot 85 (as also had Lot 31) comprised much more area than does Delta Phi Epsilon's present Lot 86, for back then it included as well what is now Lot 87 (3405 Prospect Street) and Lot 84 (1234 34th Street). It was only in the mid-1920s that Patrick A. Dempsey subdivided Lot 85 into the three modern Lots 84, 86 & 87 so that he (and his architect, the famous J.W. DeWitt Moore) could build on the vacant land next to and behind what is now the Fraternity House the twin apartment buildings that are there now.