Applegate Point West
Route 2
Applegate Point was also known as Cape Horn. Of course, this causes much confusion, since there is a much better known Cape Horn on the Columbia in Washington on Highway 14 (Old Highway 8).
The above photo is pretty clearly mislabeled, it should read "below Celilo."
I suppose there might have been a mistake made locating the photo since these cliffs resemble the one where the old tunnel was, west of the Deschutes River and east of Celilo Falls.
Looking at the imagery below from Google Earth, though, there is little doubt that the location of the old photo is between The Dalles Dam and the Trunk Railroad crossing.
If this is the correct location of the old photo, then there very well could traces of the old highway underwater in the pond south of the freeway, such as what is found further east with the Deschutes Tunnel Fragments.
The Columbia River - Cape Horns of the Columbia River
In 1867, Carleton Watkins, an early Western photographer, took a famous image of "Cape Horn near Celilo". In 2000, one of these images just sold at auction for over $200,000.
http://columbiariverimages.com/Regions/Places/cape_horns_columbia_river.html
https://artsandculture.google.com/asset/cape-horn-near-celilo/jgHifbtGTxc8MA
Columbia River Images: Cape Horn near Celilo ...
One of the Cape Horns along the Columbia River is located upstream of The Dalles, Oregon and is located at Columbia River Mile (RM) _____.
In 1873 Mrs. Frances Fuller Victor in her publication "All Over Oregon and Washington" wrote about Cape Horn near Celilo ... (p.96).
"... Aside from the river itself there is little to interest one between Dalles City and Celilo, the upper end of the gorge of the Columbia. There are rocks all about in every direction, a little grass, a great deal of sand, and some very brilliant flowers growing out of it. ... The railroad takes us along under overhanging cliffs of plutonic rock, one of which is called Cape Horn, like its brother of the lower Columbia. ...
"Cape Horn near Celilo" was located along the Celilo Canal.
Another early name for this "Cape Horn near Celilo" was "Applegate Point". This basalt cliff is not named on topographic maps.
http://columbiariverimages.com/Regions/Places/cape_horns_columbia_river.html