USGS
"CUSTER MERIDIAN"

1898

Jerry Penry
July 18, 2011

In May or June of 1898, U. S. Geological Survey topographer R. H. Chapman established a meridian line at Custer, South Dakota. The north end of the line was placed on the grounds of the Custer County courthouse. The monument was a specially marked bronze tablet set in the top of a 8"x8"x36" granite post and projected 6" above the ground. The south end of the meridian line was said to have been placed 1,510 feet to the south on the top of a rock pinnacle.

Years later, steps were built at the south entrance to the courthouse (now a museum) and someone carefully built the steps so that access to the monument could still be made. A fabricated iron plate was placed over the opening along the east edge of the steps. Gary Little of Montana located the north end of the meridian in 2010. It is known as "5316 DW" in the NGS database with PID OT0559.

While the monument at the north end of the meridian was easy to find in the courthouse steps, the monument at the south end of the meridian was more difficult. The description stated a bronze tablet was placed in a large rock, yet an extensive search failed to find the mark at the recorded distance of 1,510 feet south of the north monument. Using the stated distance, search areas were independently calculated by Gary Little, Kurt Luebke, and Jerry Penry. Gary and Kurt each searched for the south monument with no success. Kurt and Jerry, along with Jenny Stukel then searched the area again with two metal detectors going over every rock on the north face of the hill on September 3, 2010. The trees are of newer growth in the area, but the rocks and outcroppings in the area appeared to be unchanged. A large area of at least 100' feet in all directions was searched in the calculated area where the south end of the meridian should have been located, but nothing was found. A detailed search was also made on the rocks to possibly find evidence of the removal of the bronze tablet, but nothing was found.

An interesting mark was found on the top surface of a large stone that resembled a chisel-cut square and with a possible "+" in the center. This mark, however, did not match the stated distance of 1,510 feet from the north end of the meridian. Using a handheld GPS receiver on the mark at the courthouse and the mark found on the rock, the distance was found to be approximately 1,592 feet. The accuracy of the GPS at each end being about 10 feet. The longitude of the square mark found on the stone was only 1.2 seconds (0°00'01.2") different than that of the monument at the courthouse. This is a distance of 25.45' on the ground.

The stated distance of 1,510 feet proved to be where our search area went wrong. Another description was found in the magnetic station report that said the south end of the meridian was "on the top of a large rock next west from the highest rock due south of the courthouse". Not considering the distance, this description would logically place the location on top of the high ridge. On July 18, 2011, Jenny and Jerry returned to the location and searched the high rocks on top of the ridge. Using the same longitude as the position of the north end of the meridian we came to a large rock just to the west of the highest pinnacle. An initial search did not uncover any obvious marks, but upon further examination a drill hole with the remains of a bronze stem for the disk was found on top of a large rock which was west of the highest rock on the ridge. The inverse distance from the south point to the north point is approximately 1,750 feet, or 240 feet longer that what had been stated in the report.

The description stating when the Custer Meridian line was established.

The description which incorrectly states that the south end of the meridian is 1,510 feet south of the north end.

The south side of the old courthouse in Custer, South Dakota, which is now a museum.
The red arrow points to the monument marking the north end of the meridian.

The red circle shows the location of the monument located below the steps.

The metal cover over the hole that leads to the monument.

The bronze tablet for the north end of the Custer Meridian.

Looking south toward the south end of the meridian up the rock and tree covered slope.

Aerial image showing the location of the Custer Meridian based upon the incorrect distance.
The south end of the line is where the distance should have placed the south marker.

Looking north from approximately where the incorrect distance placed the south end of the meridian. The arrow points to an unknown mark.

An interesting depression in the stone that appears to be a chiseled out square.

Zoomed in and looking at the courthouse from where we originally thought the south end was located.

Jenny Stukel pointing to the true location of the south end of the Custer Meridian which was located after several previous unsuccessful attempts to find it.

Arrows point to the ends of the meridian at the courthouse (north end) and on the large rock (south end).

The remains of the 1898 bronze tablet (stem in drill hole) at the south end of the meridian.

The true location of the Custer Meridian as plotted on a USGS 7.5-minute quad sheet.

Description for the magnetic station that was placed in 1906.
This monument was not searched for during the search for the meridian line end points.
The bronze tablet bench mark mentioned is "DW 5322" which was found.

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© Jerry Penry 2011