Survey marker

Survey markers, also called survey marks, survey monuments, or geodetic marks, are objects placed to mark key survey points on the Earth's surface. They are used in geodetic and land surveying. Informally, such marks are referred to as benchmarks, although strictly speaking the term "benchmark" is reserved for marks that indicate elevation. Horizontal position markers used for triangulation are also known as triangulation stations.

Types

All sorts of different objects, ranging from the familiar brass disks to liquor bottles, clay pots, and rock cairns, have been used over the years as survey markers. Some truly monumental markers have been used to designate tripoints, or the meeting points of three or more countries. In the 19th century, these marks were often drill holes in rock ledges, crosses or triangles chiselled in rock, or copper or brass bolts sunk into bedrock.

Today in the United States, the most common geodetic survey marks are cast metal disks with stamped legends on their face set in rock ledges, embedded in the tops of concrete pillars, or affixed to the tops of pipes that have been sunk into the ground. These marks are intended to be permanent, and disturbing them is generally prohibited by federal and state law.

1877 survey marker 48

The State Line Marker is a historic boundary marker on the state line between Arkansas and Oklahoma. It is located down a path a short way north of a parking area on Talimena Scenic Drive in Ouachita National Forest, about 17 miles (27 km) northwest of Mena, Arkansas. The marker is an octagonal cast iron pipe, with the legend "48 M" on the north face (signifying its marking of the 48th mile), "1877" on the south side (the year of the marker's erection), "ARK" (for Arkansas) on the east side, and "CHOC" (for Choctaw Territory) on the west side. The pipe is mounted in a stone and mortar base installed by the United States Forest Service in 1974. The marker was placed in 1877 following a series of controversial surveys to demarcate the border between Arkansas and what was then Indian Territory.

The marker was listed on the National Register of Historic Places in 1976. This marker is one of the few surviving markers from this survey that is accessible to the public.