One wonders why there are so many survey markers on or near the summit of Mt. Whitney. There is one survey marker that should have been mentioned above that was not mentioned. I think this marker and its data sheet should resolve the crux of the matter. This is NGS marker GTO237 not to be confused with GTO238. This marker is a vertical marker with a high "Vertical Order" of accuracy. Being a vertical marker with a high order makes it is more accurate than any horizontal marker regarding elevation. Many of the other markers on the summit are horizontal markers. GTO237 states the height as 14,502.7 ft or 4421 meters. Now about the 14,505 ft elevation indicated on the 1811 data sheet? I think elevation 14,505 as indicated on the 1811 data sheet is probably referring to the total height of the peak not marker 1811 only. According to data sheet GTO237 it says: "AT THE SUMMIT OF MT. WHITNEY, TULARE COUNTY, 6.5 FEET SOUTH AND 5 FEET WEST OF THE CENTER OF A ROCK MONUMENT IN WHICH IT IS SET. Now this height of 14,502.7 is not the total height because this marker or disc is not located on the highest point on the monument but located on the monuments side. So, if one takes 14,502.7 and adds another 2 feet to indicate the top of this monument, the height of Mt. Whitney would be very close to if not 14,505 ft. I think this what the NGS is indicating on its 1811 data sheet, the data sheet everybody seems to quote from. So lets be confident in the 14,505 ft. elevation. By the way all the other survey markers other than GTO237 are positioned in Inyo County. –Making the highest point in the lower 48 states (really lower 49) in Tulare County not in Inyo!