I mention the McDowell map a lot. To me it is a “primary source” of great value. The map depicts the topography, roads, and places of Northern Virginia in fine detail. It is also the worksheet over which Federal officers planned operations. If they needed to move from the ubiquitous “Point A” to “Point B” then it was this map which depicted the relation of the two points, and the road structure between.
To the left side of the map, and unfortunately blocking some of Fauquier County, is a section of text which I have been snipping around to create the maps used of late. It is titled “Data used in compilation.”
Let me attempt a transcription of this so you don’t have to break out the glasses:
Surveys – by John J. Young, Wm. H. Paine and others under the direction of Top. Engineers over that portion of Virginia included between the river Potomac and a line from Chain Bridge, via Minor’s Hill, Peach Grove, Vienna, Fairfax C.H., Annandale, Springfield Station, and Accotink to Mount Vernon, also along the turnpike from Prospect Hill to Drainsville [sic].
Surveys – by Capt. Preston C.F. West Vol. T.E. Smith’s Division & by Coast Survey parties under direction of Lieut. Col. Macomb T.E., A.D.C. Leesburg Turnpike from Falls Ch. to Sugerland Run, also Georgetown Turnpike from Prospect Hill to Chain Bridge and Country between it and Potomac. Comparisons have been made with such other Coast Survey Charts as could be obtained especially with that furnished by Genl. Franklin of the Country occupied by his Division.
Reconnaissances – by Lt. Col. Macomb, Top. Eng. beyond Drainesville [sic] by Maj. Palmer, T.E. to Mathias Point, White House point and to Flint Hill by Capt. Williamson opposite Quantico Creek, by 1st Lt. Abbot, T.E. about Blackburns Ford and Vicinity, by Capt. Schumacher, V.T.E. to Genl. King’s Brig. of his outposts by Capt. Wm. Heine, V.T.E. to Genl. Heintzelman’s Div. of Country about Bone Mill and toward Wolf Run shoals by Top. Engineers and other U.S. officers to Centreville and Sudley Springs.
Informations – furnished by Genl. McCall, Gen. Meade, and Gen. Reynolds in vicinity of Drainesville [sic] and Difficult Cr. and between turnpike and the Potomac.
Informations – furnished from Gen. Hancock, Gen. Brannan, and Capt. West Vol. T.E. of Country occupied by Smith’s Division.
Informations – furnished by General Morell and General Butterfield of Country occupied by Gen. Fitz John Porter’s Division.
Informations – furnished by officers attached to Gen. Wadsworth’s, Gen. King’s, and Gen. Augur’s Brigades.
Informations – furnished by Maj. Forstner, Vol. T.E. to Gen. Blenker’s Division.
Informations – furnished by Gen. Franklin.
Informations – from Gen. Hooker of country occupied by his div, – also from Col. Ch. Scranton & Mess W.H. Scranton, Hiles, Hornbucker, Burd, Gaston, Arnhast, Gregg, Dills, Athey.
Informations – obtained by Gen. Richardson and Capt. Wm. Heine, Vol. T.E. to Gen. Heintzelman’s Division beyond outposts and towards the Occoquan.
Informations – given by Mr. Roberts & furnished by Gen. Kearney, Country about the Occoquan, etc.
Informations – given by Lt. Col. Alexander Engs. U.S.A. & Mr. Hawshurst, County about Fryingpan etc.
Map – N.E part of Dist. of Columbia by A. Boschke.
Map – State of Virginia by Herrman Boye, corrected 1859 by L. V. Buchholtz.
Map – furnished by Bureau T.E. Survey for Great Falls Aqueduct by Lieut. M.C. Meigs Corps of Engineers, 1852.
Map – Mt. Vernon estate by Wm. Gillingham.
Map – Loudoun County by Yardley Taylor.
Map – Orange and Alexandria Railway, by August Faul.
Manuscript – N.E. part of Virginia by the Bureau of Topographical Engineers.
Manuscript – Accotink Turnpike by Gen. Geo. Washington.
Manuscript – Loudoun & Hampshire Railway 1854.
Manuscript – Manassas Gap independent Line of Railway 1853.
Manuscript – Projected Canal between Goose Creek and Alexandria by Baldwin.
Additions & Corrections – for Rappahannock and Rapid Ann [sic] Rivers and their vicinity furnished from the Records in Office of Lt. Col. J.N. Macomb, A.D. Camp and Ch. Top. Eng. Army of Potomac.
The list of sources is like a “who’s who” of the Army of the Potomac. Too many names for me to tag for this post.
And George Washington! That tells us something about the detail and accuracy of the work done by our first president. It also tells us how inclusive the scope set by the officers compiling the information shown on the map.