Old Bethpage in Nassau County, New York — The American Northeast (Mid-Atlantic)

M551 Sheridan

Photographed by Ian Lefkowitz, October 26, 2025

1. M551 Sheridan Marker

Inscription. The M551 Sheridan was designed to be dropped by parachute from C-130 cargo planes and to be capable of fording rivers to ensure that American mobile forces would always have the armored support they required. While the concept made good sense on paper, much like WWII's Locust tank (also on display at this museum) the Sheridan’s operational history did not go as planned.

Plagued with design issues and cost overruns, it was armed with a technically advanced but troublesome gun/missile launcher that in combat, would initially “cook off” rounds before they were fired. Just firing the gun could adversely impact the tank’s electronics.

Sent to Vietnam shortly after entering service, other serious operational problems were quickly revealed. These included having inadequate protection from mines and rocket-propelled grenades.

With a four-man crew, it would see limited action in Operation Just Cause against the Panamanian dictator Manuel Noriega, and again during the Persian Gulf War.

Because of its light weight and 300hp diesel engine, it was capable of on-road speeds of up to 43 mph.

Erected by The Museum of American Armor.

Topics. This historical marker is listed in these topic lists: Military

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• Roads & Vehicles • War, Vietnam.

Location. 40° 46.491′ N, 73° 26.774′ W. Marker is in Old Bethpage, New York, in Nassau County. It is on Round Swamp Road. Touch for map. Marker is at or near this postal address: 1303 Round Swamp Road, Plainview NY 11803, United States of America. Touch for directions.

Regionally, this marker is in the New York City Metropolitan Area

and on Long Island.

It is also in the American Northeast

and in the Mid-Atlantic.

Globally, it is in the North Atlantic Region,

North America,

the Western Hemisphere,

the Western World,

and the Anglosphere.

Historically, it finds itself in what was once New Netherland

and also one of the original Thirteen Colonies.

Other nearby markers. At least 8 other markers are within walking distance of this marker: M42 Duster (here, next to this marker); M110 Howitzer (here, next to this marker); Long Island During the Cold War (about 300 feet away, measured in a direct line); M47 Patton Tank (about 300 feet away); The U.S. M1 155mm Gun (about 300 feet away); T-72 Main Battle Tank (about 300 feet away); BA-64 Armored Scout Car (about 300 feet away); M42B1 Sherman Flamethrower (about 300 feet away). Touch for a list and map of all markers in Old Bethpage.

Also see . . . The Noble (but Doomed) M551 Sheridan in Vietnam (The Armory Life).

The M551 Sheridan Light Tank, an ambitious project designed to deliver powerful armored support to U.S. troops, ultimately fell short of its potential due to various design and operational issues.

(Submitted on November 15, 2025, by Ian Lefkowitz of New York, New York.)

Photographed by Ian Lefkowitz, October 26, 2025

2. M551 Sheridan Marker

The marker is on the right of three adjacent markers near the Museum of American Armor.

Photographed by Ian Lefkowitz, October 26, 2025

3. M551 Sheridan Marker

The M551 Sheridan is not on display near the historic marker.

Credits. This page was last revised on November 16, 2025. It was originally submitted on November 15, 2025, by Ian Lefkowitz of New York, New York. This page has been viewed 45 times since then and 17 times this year. Photos: 1, 2, 3. submitted on November 15, 2025, by Ian Lefkowitz of New York, New York. • Andrew Ruppenstein was the editor who published this page.