Navy, was laid down by the Maryland Steel Co. 23 March 1910; launched 21 January 1911; and placed in service with a merchant crew at Norfolk Navy Yard 20 September 1911. Neptune commissioned with a naval complement 7 December 1914 and resumed collier service with the Atlantic Fleet.
Assigned to the Auxiliary Division, Atlantic Fleet on 28 December 1915, she continued this duty into 1917. When the United States entered World War I, Neptune was at Baltimore, Maryland, loading general cargo. Departing that port, she put into Norfolk to embark a division of the 1st Aeronautical Detachment and sailed 25 May 1917 for France escorted by destroyers Jarvis and Perkins. Neptune sailed for home 28 June, arriving at New York on 11 July.
The vessel again resumed service with the Train, Atlantic Fleet, making one voyage to the Caribbean, 12 July to 27 August, and then operated off the Atlantic Coast, delivering coal to ports in Chesapeake Bay through the end of the war. In 1919, following three voyages to Guantanamo Bay to supply naval forces at the training base there, the collier departed Norfolk on 3 October for the Pacific, calling en route at the Panama Canal Zone, Nicaragua, and Honduras with Marines and cargo and arriving at San Diego on 20 October. Returning to the east coast the way she came, the collier arrived at Norfolk on 20 January 1920. Neptune made another coaling voyage to the west coast before departing Philadelphia on 27 August for an eleven-month cruise as part of the Train, Pacific Fleet. She visited Pearl Harbor from 8 September to 25 October and cruised to Valparaíso, Chile in January and February 1921 to coal units of the Battle Force engaged in maneuvers off the Chilean coast.
Towed by tugs Kalmia and Wandank, Neptune departed Boston 14 December on her last voyage, arriving at Philadelphia three days later. Please inspect the pictures, as they give the best representation of condition. May have discoloring, edge or corner wear, marks, creases, fading, smudges, corner or edge bends, tears, or corners missing.