CathedralGrove.eu has some interesting information about this tree.
The "Dead Giant" is a famous Sequoia stump located on the first stage road into Yosemite Valley, in the Tuolumne Grove of what is now Yosemite National Park. The veteran Sequoia tree had been struck by lightening but was still living when she was cut down at 90 ft from the ground and debarked. Tunneled c. 1875 to entice stagecoach tourists from San Francisco, this was the first of California's "Drive Thru" trees - macabre roadside displays created to provide entertainment and recreation.
YosemiteHikes.com has this map.