Greenwich in Greater London, England, United Kingdom — Northwestern Europe (the British Isles)

Ordnance Survey Bench Mark

Public Standards of Length

Photographed by Michael Herrick, April 28, 2018

1. Ordnance Survey Bench Mark Marker

Inscription.
Ordnance Survey Bench Mark
The small plate (marked ‘G1692’) is an Ordnance Survey bench mark. Similar marks appear on walls and buildings across the country. The height of each above sea level has been measured and recorded. Dating from the 1940s, this particular mark is a replacement for an older mark that once existed nearby.

Public Standards of Length
These British Imperial Standards were first mounted outside the Observatory main gates some time before 1866, to enable the public to check measures of length.

The stated length is the distance between the inner faces of the two D-shaped studs.

Topics. This historical marker is listed in these topic lists: Industry & Commerce • Science & Medicine.

Location. 51° 28.681′ N, 0° 0.083′ W. Marker is in Greenwich, England, in Greater London. It can be reached from the intersection of Blackheath Avenue and Great Cross Avenue, on the left when traveling north. Located at the Royal Observatory Greenwich. Touch for map. Marker is in this post office area: Greenwich, England SE10 8XJ, United Kingdom. Touch for directions.

Regionally,

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this marker is in the Greater South East.

Globally, it is on the Atlantic Ocean,

in the North Atlantic Region,

in Europe,

in Atlantic Europe,

on one of the British Isles,

in the Western World,

and in the Anglosphere.

Historically, it finds itself in what was once the Roman Empire.

Other nearby markers. At least 8 other markers are within walking distance of this marker: The Shepherd 24-hour Gate Clock (here, next to this marker); Greenwich Meridian Marker, 1750-1851 (a few steps from this marker); Time for everyone (a few steps from this marker); Airy’s meridian line (a few steps from this marker); The Greenwich Meridian Telescope (a few steps from this marker); Bradley’s meridian line (a few steps from this marker); Family Tombstone of Edmund Halley (within shouting distance of this marker); Flamsteed’s Well Telescope (within shouting distance of this marker). Touch for a list and map of all markers in Greenwich.

Also see . . . Royal Observatory, Greenwich on Wikipedia. (Submitted on May 24, 2018, by Michael Herrick of Southbury, Connecticut.)

Photographed by Michael Herrick, April 28, 2018

2. Ordnance Survey Bench Mark Marker

Next to the marker is the Ordnance Survey Bench Mark. Below are the Public Standards of Length.

Ordnance Survey Bench Mark image. Click for full size.

Photographed by Adam Margolis, June 16, 2026

3. Ordnance Survey Bench Mark

Photographed by Adam Margolis, June 16, 2026

4. Ordnance Survey Bench Mark Marker

Credits. This page was last revised on July 9, 2026. It was originally submitted on May 24, 2018, by Michael Herrick of Southbury, Connecticut. This page has been viewed 829 times since then and 40 times this year. Photos: 1, 2. submitted on May 24, 2018, by Michael Herrick of Southbury, Connecticut. 3, 4. submitted on June 30, 2026, by Adam Margolis of Mission Viejo, California.