Triangulation Station

1893 & 1925

Jerry Penry
May 30, 2010

Custer Peak, named for General George A. Custer, is a prominent mountain in the Black Hills located south of the towns of Deadwood and Lead. The peak was the location for one of the original USGS triangulation stations in 1893. The original description described the triangulation station as being a "rock monument about 6' high and 5' in diameter at the base with a pine pole in center". It is unclear if that meant an actual single rock formation or possibly a pile of rocks. Neither exist on the mountain today at the calculated location, but a flag pole now stands at or very near to that original location.

In 1925, USC&GS occupied the peak and placed a brass cap on an iron pipe near the location of the USGS monument location. Similar monuments were also placed during that year by USC&GS on other peaks such as Bear Butte near the orginal USGS monuments that were of lesser quality. Custer Peak has a well maintained lookout tower. The triangulation station and the three reference marks are all near the tower. The Coast & Geodetic Survey (NGS) datasheet for this station is PU2338. In 1950, C&GS established Reference Mark No. 3 as well as the Azimuth Mark. The disks for these two markers are both dated 1925.

There are also a few other small buildings as well as the ruins of two much older structures on the peak. The peak can be reached by 4-wheel drive vehicle in dry weather. The road to the peak is very narrow, so meeting an oncoming vehicle can be a very close experience.

The west side of the lookout tower on Custer Peak.

Jerry Penry pointing to the 1925 USC&GS triangulation station next to the north wall of the lookout tower.

Close-up view of the 1925 brass cap on iron pipe.

Looking northeast toward the base of the north wall where the 1925 triangulation station is located.

View looking straight down along the north wall from the walkway around the base of the lookout tower.

Reference Mark No. 1.

Close-up view of Reference Mark No. 1.

Reference Mark No. 2.

Close-up view of Reference Mark No. 2.

Reference Mark No. 3.

Close-up view of Reference Mark No. 3. It is stamped for the year 1925, but was placed in 1950.

View of Bear Butte located northeast of Sturgis. This peak contained both an 1893 and 1925 triangulation station which Custer Peak connected with during both surveys.

Harney Peak is the highest peak in the photo and highest peak in the Black Hills. This was a connection point from Custer Peak during both the 1893 and 1925 surveys.

The flag pole on Custer Peak. This is believed to be the original location for the USGS 1893 triangulation station that was described as being a "Pine pole in a 6' high rock".

A pole with a barrel for unknown use located southwest of the lookout tower.

Possibly a current outhouse for occupants of the lookout tower.

Another building on Custer Peak which is probably a tool house.

Ruins of a building showing early habitation on Custer Peak.

Ruins of another building on Custer Peak located north of the current lookout tower.

A chipmunk calls the peak his home. Several were seen scurrying around the lookout tower area.

The Azimuth Mark for Custer Peak.

Close-up view of the Azimuth Mark. It is stamped for the year 1925, but was placed in 1950.

View in the direction of Custer Peak from the Azimuth Mark. The trees have now obscured the view to the triangulation station.

Back to USGS Black Hills Triangulation

© Jerry Penry 2010