_501 Cameron Street_, Alexandria. This is believed to be the "large and comodious" dwelling which, according to an 1823 entry in the _Alexandria Gazette_, Mason was renting at the corner of Cameron and Pitt Streets. The house is a three-story brick structure, probably built during the first quarter of the nineteenth century. It is still standing. (_Alexandria Gazette_, March 13, 1823 and November 1, 1833.) _Colross_, Alexandria, 1100 block of Oronoco Street, block between Oronoco, Pendleton, North Henry and North Fayette. This was an existing house built in the last quarter of the eighteenth century, acquired by Thomson F. Mason in 1833. Mason was buried in a tomb behind the mansion after his death in 1838. The main house was moved to Princeton, New Jersey, in 1929 and rebuilt there. Today the block in Alexandria includes a warehouse, car wash, automobile repair facility and a transformer station. The present location of the remains of Thomson F. Mason, removed from Colross, is not known to the writer. (Mary G. Powell, _The History of Alexandria_, Va., Richmond, Wm. Byrd Press, 1928, p. 261; _New York Herald Tribune_, July 7, 1929, "Colross Built 1785, to come to Jersey site."; Mrs. Betty Carter Smoot, _Days in an Old Town_, Alexandria, privately printed, 1934, pp. 121-32; Henry H. Saylor, _Alexandria Virginia_, The White Pine Series, New York, Russell F. Whitehead, 1926, (photographs and drawings); plus additional material available in the Alexandria Public Library.) _The Hallowell School_, 609 Oronoco Street, Alexandria. A two-and-a-half-story brick structure, built circa 1800, it is the companion house to the Lee Home, next door at 607 Oronoco. At 609, Benjamin Hallowell operated a school among whose students was Robert E. Lee. T.F. Mason acquired the house after the Hallowell School moved elsewhere, at public auction on February 9, 1835, though he may have lived there earlier as a tenant. By the time of purchase he was already a resident at Colross, but a sale advertisement for 609 Oronoco Street in 1839 calls it "... the late residence of the Honorable T. F. Mason ...". The house is still standing. (Deering Davis, Stephen P. Dorsey and Ralph Cole Hall, _Alexandria Houses_, Cornwall, N.Y. Architectural Book Publishing Co., Inc., 1946, pp. 88-89, 126; Benjamin Hallowell, _Autobiography_, Philadelphia, Friends Book Association, 1884, pp. 95-120. _Alexandria Gazette_, August 30, 1839,; Alexandria Deed Book V-2, p. 355(1835).) _Huntley_, 6918 Harrison Lane, Groveton, Fairfax County. Still standing. Though Huntley was built during Mason's ownership of the property, no record has been found that he actually lived there.