Survey Mark Hunting

Survey marks or monuments are objects used to mark a precise location and/or elevation on the earth. The markers most survey mark hunters look for most often are 4-inch brass or aluminum disks installed into a stable setting like bedrock, an embedded boulder, a specially-poured concrete monument, a large building or bridge. Earlier survey monuments were made of stone or even buried bottles or jugs.

Some other types of survey marks are also included in the database, such as landmark stations—tall structures that can be sighted on from a distance so that trigonometric calculations can be made. Airway beacons are of this type.

Survey mark hunting, sometimes referred to as “benchmark hunting” regardless of the type of marker being sought, is simply the activity of searching for these survey marks. When we find, or “recover,” a mark, we do not take it or disturb it in any way. We document the mark’s condition and make note of any updates to the description and geographic coordinates that we think are needed. Then, when applicable, we send our report to the National Geodetic Survey (NGS) or the U. S. Geological Survey (USGS).

Learn more …

Getting Started

Geodetic Glossary (HTML version)

This is a hypertext version of the 1986 publication by the National Geodetic Survey (also available in .pdf format)

NGS Survey Mark FAQ

NGS provides answers to some basic questions about survey marks and datasheets.

USGS Guide to Land Survey Benchmarks

USGS has a guide to basic information about survey marks and how to find them.

Standard Numbered Notes for Description of Marks

This excerpt from The Manual of Geodetic Triangulation is useful when you’re out in the field and the mark descriptions refer to Note 4, Note 11, etc.

Joy of Geodetics

For a very deep dive, The United States Power Squadrons have provided a series of presentations to instruct members on methods of surveying, types of markers, and procedures for reporting recoveries.