named for a local settler, A. J. Tetherow, a pioneer stockman and a member of a prominent early pioneer family of the Willamette Valley. He had a farm on Crooked River and a ferry on Deschutes River, near the present site of the bridge. This information was furnished by J. N. Williamson of Prineville.
Thatcher, Washington County. Thatcher is a cross-roads community about three miles northwest of Forest Grove and close to the northeast slope of David Hill. The place was named for Harmon and Jemima Thatcher who took up a homestead in the locality in early pioneer days. The Thatchers were married in Indiana in 1847 and came to Oregon soon afterward. Thatcher post office was established August 3, 1895, with Thomas J. Clark first postmaster. The office was closed August 21, 1902.
Thayer Glacier, Deschutes County. This glacier is on the eastern part of the North Sister. It was named by Professor E. T. Hodge of the University of Oregon for Eli Thayer, representative in Congress from Massachusetts, who assisted in securing the passage of the bill admitting Oregon to the Union. See Mount Multnomah, page 75. For information about Oregon's debt to Thayer, see Scott's History of the Oregon Country, volume V, page 3.
The Dalles, Wasco County. The name The Dalles is derived from the French word dalle, meaning flag-stone, and was applied to the narrows of the Columbia River, above the present city of The Dalles, by French-Canadian employees of the fur companies. Among other things, dalle meant a stone used to flag gutters, and the peculiar basalt formation along the narrows doubtless suggested gutters. The word dalles signified, to the voyageurs, the river rapids flowing swifty through a narrow channel over flat, basaltic rocks. The name is common in America. Well-known dalles are those of the Saint Louis, Saint Croix, Wisconsin, and Columbia rivers. The best known dalles are those of the Columbia. The name is not derived from the French dale meaning trough. As far as the compiler knows the first use of the name Dalles in Oregon is in Franchere's Narrative, on April 12, 1814, where it is used to describe the Long Narrows. John Work, in his journal of 1825, speaks of Dalls. The name La Grande Dalle de la Columbia became established. The incorporated name of the community is now Dalles City, but the postal name, and the one in universal use is The Dalles, this style being adopted not only for historical and sentimental reasons but also to avoid duplication with Dallas, Polk County. The post office was established with the name Dalles on November 5, 1851, with William R. Gibson first postmaster. On September 3, 1853, the name was changed to Wascopum, and on March 22, 1860, it was changed to The Dalles. The narrows of the river are generally known as The Dalles of the Columbia, and this collective term describes the geographic features from the Big Eddy on the west to Celilo Falls on the east. Just east of Big Eddy is Fivemile Rapids, formerly known as the Long Narrows, The Dalles or The Great Dalles. Further east is Tenmile Rapids, formerly known as the Short Narrows, Little Narrows or Les Petites Dalles. For information about The Dalles of the Columbia, see OHQ, March, 1926, in the article by Henry J. Biddle entitled "Wishram." The neighborhood of Mill Creek at The Dalles was called Quenett by the Indians, which was a word for salmon trout. Lewis and Clark camped
