Trips Places Foods Stories Newsletters
Loading...
Loading...
Loading...
Loading...

No search results found for
“”

Make sure words are spelled correctly.

Try searching for a travel destination.

Places near me Random place

Popular Destinations

  • Paris
  • London
  • New York
  • Berlin
  • Rome
  • Los Angeles
Trips Places Foods Stories Newsletters
Sign In Join
Places near me Random place
All the United States Washington, D.C. Washington Mini Monument
AO Edited

Washington Mini Monument

There's a 12-foot-tall replica of the Washington Monument hidden under a manhole nearby.

Washington, D.C.

Added By
Elliot Carter
Email
Been Here
Want to go
Added to list
CAPTION
Detail of the Mini Monument   NOAA's National Geodetic Survey
  NOAA's National Geodetic Survey
  NOAA's National Geodetic Survey
Yellow dashes indicate modern ground level   Mathew Brady
Detail of the Washington Monument foundation   Library of Congress
Hidden at the moment   notoriousFIG / Atlas Obscura User
White arrow marks the Mini Monument  
A view through a hole in the cover (photo by S.Clark).   jplivolsi / Atlas Obscura User
  ambentzen / Atlas Obscura User
Been Here
Want to go
Added to list

About

Unknown to most passersby, there's a 12-foot-tall replica of the Washington Monument under a manhole near the actual monument.

Officially known as "Bench Mark A," this underground oddity is actually a Geodetic Control Point that’s used by surveyors. It’s part of the network of a million control points across the country that helps the National Geodetic Survey (NGS) synchronize all of the government’s maps.  

According to NGS modernization manager Dru Smith, “Geodetic control points provide starting points for any map or measurement. It has to be more accurate than any measurement you do on top of it, so we pick things that tend to be extremely stable.”

Usually that means metal caps or rods that are driven down into the ground, but this quirky control point mirrors the form of its next-door neighbor.

“All the surveys we’ve done, going back to the early 1900s, have used it,” says Smith. Most recently, it was used in the aftermath of the 2011 Washington earthquake. Measurements over the past century have shown that the marshy soil below Washington Monument has risen 6.2 centimeters, at an average rate of 0.5 millimeters per year.

The mini monument was placed in the 1880s as a part of a trans-continental leveling program. The ground level here was much lower at that time, with large parts of the Washington Monument foundation still visible above ground (see fourth image above). The mini monument was above ground for a time, before being encased in a brick chimney and buried. Outside of surveying circles, it’s been largely forgotten.

Related Tags

Monuments History Maps Government Marvelous Maps And Measures Geographic Markers Miniatures Small Worlds And Model Towns

Know Before You Go

The survey marker is underneath a manhole, just south of the Washington Monument.

The manhole cover can only be opened with a key. The park rangers don’t have a key (and many have never seen it themselves) so it would take some investigating to figure out who might be able to give access.  

Community Contributors

Added By

Elliot Carter

Edited By

Mom0ja, ernestdubrul, jplivolsi, notoriousFIG...

  • Mom0ja
  • ernestdubrul
  • jplivolsi
  • notoriousFIG
  • ambentzen

Published

February 7, 2017

Edit this listing

Make an Edit
Add Photos
Sources
  • Phone interview with Dru Smith, 1/26/2017
Washington Mini Monument
2 15th St NW
Washington, District of Columbia
United States
38.889098, -77.035246
Get Directions

Nearby Places

Washington Monument Lightning Rod

Washington, D.C.

miles away

Washington Monument Access Hatch

Washington, D.C.

miles away

Washington Monument Commemorative Stones

Washington, D.C.

miles away

Explore the Destination Guide

Photo of Washington, D.C.

Washington, D.C.

United States

Places 285
Stories 49

Nearby Places

Washington Monument Lightning Rod

Washington, D.C.

miles away

Washington Monument Access Hatch

Washington, D.C.

miles away

Washington Monument Commemorative Stones

Washington, D.C.

miles away

Explore the Destination Guide

Photo of Washington, D.C.

Washington, D.C.

United States

Places 285
Stories 49

Related Stories and Lists

6 Secrets of the Washington Monument

List

By Elliot Carter

Related Places

  • Nice view down Memorial Avenue.

    Arlington, Virginia

    Pierre L’Enfant’s (Second) Gravesite

    The controversial urban planner who designed Washington, D.C., was buried in Maryland, and can presently be found in Virginia.

  • Monument to the geographic center of Belgium

    Walhain, Belgium

    Geographic Center of Belgium

    This metal monument marking the middle of Belgium represents three regions coming together to form one country.

  • Ras Angela

    Ras Angela, Tunisia

    Ras Angela

    The northernmost point of continental Africa—or is it?

  • Marco do Equador on Ilhéu das Rolas

    Ilhéu das Rolas, São Tomé and Príncipe

    Marco do Equador

    The equator passes through this tiny island in the eastern Atlantic.

  • Historical sign in Osborne, Kansas.

    Osborne, Kansas

    Geodetic Center of North America

    This lesser-known geographic marker was the reference point for all surveys of the continent for 75 years.

  • Stockholm, Sweden

    1/4 Milestone of Stockholm

    This stone obelisk is a relic of the 17th-century Swedish mile markers.

  • The Powell Memorial.

    Grand Canyon Village, Arizona

    Powell Memorial

    A monument to the one-armed geologist who led the first documented expeditions through the Grand Canyon.

  • The stone has been worn down a bit over the years.

    Washington, D.C.

    District of Columbia Center Point

    A little marble compass above George Washington's (empty) tomb in the Capitol marks where D.C.'s four quadrants intersect.

Aerial image of Vietnam, displaying the picturesque rice terraces, characterized by their layered, verdant fields.
Atlas Obscura Membership

Become an Atlas Obscura Member


Join our community of curious explorers.

Become a Member

Get Our Email Newsletter

Follow Us

Facebook YouTube TikTok Instagram Pinterest RSS Feed

Get the app

Download the App
Download on the Apple App Store Get it on Google Play
  • All Places
  • Latest Places
  • Most Popular
  • Places to Eat
  • Random
  • Nearby
  • Add a Place
  • Stories
  • Food & Drink
  • Itineraries
  • Lists
  • Video
  • Podcast
  • Newsletters
  • All Trips
  • Family Trip
  • Food & Drink
  • History & Culture
  • Wildlife & Nature
  • FAQ
  • Membership
  • Feedback & Ideas
  • Community Guidelines
  • Product Blog
  • Unique Gifts
  • Work With Us
  • About
  • FAQ
  • Advertise With Us
  • Advertising Guidelines
  • Privacy Policy
  • Cookie Policy
  • Terms of Use
Atlas Obscura

© 2025 Atlas Obscura. All Rights Reserved.