Camp Washington might be "Camp Washington, DC", one of the "City Camps" located around the French city of Reims.
Troops would pass through these camps on the way to the "Cigarette Camps" at Le Harve.
There were more camps around Antwerp as well as camps north of Marsailles in Southern France but i havent found anything on those yet.
http://www.skylighters.org/citycamps/
The U. S. Army's redeployment camps (repo-depos) around the French city of Reims were all named after American cities. Reims itself became the headquarters of the Assembly Area Command, which was the central organizing entity for these camps. (Information on these "'tent" camps is sparse,
CAMP NAME LOCATION
Atlanta — —
Baltimore 25 miles SE of Reims —
Boston — —
Brooklyn — —
Chicago —
Cleveland — —
Des Moines — —
Detroit Northwest of Reims
Miami — —
New Orleans — —
New York Suippes Sub-Area, 40 km SE of Reims —
Norfolk — —
Oklahoma City — —
Philadelphia — —
Pittsburgh — —
San Antonio — —
St. Louis near Verzenay, approx. 15 km south of Reims —
Washington, D. C. —
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http://www.skylighters.org/special/cigcamps/cigintro.html
The Cigarette Camps
Most of the camps were located between Le Havre and Rouen.
Camp Herbert Tareyton, located in the Forest of Montgeon within the city limits, with a capacity of 16,400 men.
Camp Wings, capacity of 2,250 men, was situated on the grounds of the Blaville Aerodrome.
Camp Home Run, at Sanvic, capacity 2,000 men;
Camp Philip Morris, at Gainneville, held 35,000 men;
Camp Pall Mall, at Etretat, provided rather soggy billets for 7,700 men.
Camp Lucky Strike, located between Cany and Saint-Valery (capacity 58,000);
Camp Old Gold, at Ourville (capacity 35,000); and
Camp Twenty Grand, at Duclair (capacity 20,000).
Camp Chesterfield (Information about Camp Chesterfield is very sparse)
Camp Tophat, on the outskirts of Antwerp, Belgium, also qualified (technically) as a Cigarette Camp since it was named after Belgian Tophat cigarettes.