Petroglyph Canyon is now underwater in Horse Thief Lake. The underwater area is now a registered National Historic Place, significant to the native peoples of the area, and also as an area noted by Clark during the Lewis and Clark Expedition. On the Historic Register site the pictographs are listed as dating from 1000-1500 AD.
There are hundreds of petroglyphs underwater. Only a few were saved, and they are now located at the historic site of the people of Wishram Village. (Be sure to look at other petroglyph pictures in the gallery). Now called Columbia Hills State Park (previously known as Horse Thief State Park) the petroglyphs have been lined up along a short path. There is also a trail next to the interpretive area, but it is available only by guided tour on Saturdays due to problems with vandalism.
Lewis and Clark stayed at the village in 1805, and Clark wrote this in his journal: "I returned through a rockey open country infested with pole-cats to the village where I met with Capt. Lewis the two old Chiefs who accompanied us & the party & canoes who had all arrived Safe; the Canoes haveing taken in Some water at the last rapids. here we formed a Camp near the Village, ..." [Clark, October 24, 1805]
If you are in the area, be sure to hike up nearby Horse Thief Butte. This place is the home of the "She Who Watches" petroglyph, and is also a favorite of local rock climbers.