Vintage 1939 linen postcard featuring an elevated view of Roosevelt Dam and its reservoir along the Apache Trail, approximately 79 miles east of Phoenix, Arizona. The reverse identifies the structure as the largest dam in the Salt River irrigation project at that time and notes its importance in supplying power and water to the Phoenix area. Issued by the Union Oil Company of California as No. 63 in its Natural Color Photographic Scenes of the West series, with the classic “See the West with 76 Gasoline” advertising logo. An appealing collectible for enthusiasts of Arizona history, historic dams, Western engineering, Apache Trail tourism, and Union 76 petroleum advertising.