The First Map To Name Oregon Territory and The Finest Map of North America Published in America in the First Half of the 19th Century
Tanner's landmark map of North America, first issued in 1822, is perhaps the most important North American map of the 19th Century published in America.
The map several highly important "firsts" in the American Northwest, including
- first map to name Oregon Territory
- first map to show the 1821 Decree of Czar Alexander I, claiming the Northwest part of America north of 51 degrees.
As noted by James Walker:
Tanner’s [map] represents a significant placeholder in the early American literature on continental expansion of the republic to the West. The map was included in the fourth folio of Tanner’s New American Atlas, published in late 1822. A masterful summary of information derived from existing maps and travel and government documents, it is the first printed map to apply to the region the name “Oregon Terry." Tanner . . . likely adopted this toponym from Congressman John Floyd from Virginia, who introduced a bill in January 1822 to establish a “Territory of Origon” [sic] on the Pacific Coast.
. . . Tanner’s “Oregon Terry.” extends from the Missouri River to the Pacific Ocean, suggesting an American right of possession of transcontinental territory because of proximity both to the Columbia River and to regions east of the Rocky Mountains, where sovereignty already had been claimed or established. Tanner does not extend the 49th parallel boundary west of the Rocky Mountains, implying that the American territorial claims to the north were valid.
Tanner’s is the first map to name “Long’s Peak” and may be the first to identify the proposed Ukase (decree) of Tsar Alexander I of Russia in 1821, which claimed Russian sovereignty in the Pacific Northwest above latitude 51 degrees.
The map illustrates the extent of the discoveries of Lewis & Clark, and combines the information from the expeditions of Pike, James, and a host of other overland surveys, into this spectacular large format work.
The treatment of the Mississippi and Missouri Valleys is extraordinary, as is the detail along the Columbia River Basin. The map also illustrates the two mythical rivers flowing from the area just west of the Rocky Mountains to the Pacific, draining the mythical lakes of Timpanogos and Teguayo. Tanner's treatment of the Rocky Mountain Region, Texas, Oregon Territory and Hudson Bay Company lands are also truly noteworthy.
In describing the southwestern sheet, Warren Heckrotte notes:
The interior [of California] is devoid of topography except for the three great rivers which rise in the interior and course through California to the Pacific Ocean. The idea of these rivers grew out of distortions of reports and extrapolations from earlier Spanish missionary explorers, and no doubt an element of hope of a water passage from the interior to the coast. For a brief period these rivers were a pervasive myth of the geography of this part of the west.
Jedediah Smith, in his first expedition to California, searched for one of these rivers. Even Fremont, in the 1840s by which time it was clear these rivers did not exist, sought a passageway through the Sierra Nevada that one of these rivers might provide.
Tanner, though showing these rivers, introduces a cautionary note on the map. The information upon which these rivers is based is not of an "authentic character" and it is "very doubtful-whether the courses and magnitude of those streams, should be relied on as correct." Nevertheless, if it should prove to be "essentially correct," Tanner states that it will be "a source of satisfaction" to him.
Tanner's representation of the California coast bears no resemblance to the actual coastline and it is curious that he neglected Vancouver's charts of the California coast (map 18), even while following Vancouver for the coastline north of California. With the exception of this part of the west, Tanner's map is a skillful compilation of the available information from explorations of the west that provides an accurate description for this period.
The map was issued separately and also bound in four sheets into Tanner's New American Atlas, which was issued in serial subscription format and later as a bound volume, beginning in 1823.
Tanner's map is one of the milestones in American map making, both for its content and beauty.