The moated manor house of Baddesley Clinton in Warwickshire, England

A moat is a deep, broad ditch, either dry or filled with water, that surrounds a castle, other building or town, historically to provide it with a preliminary line of defence. In some places moats evolved into more extensive water defences, including natural or artificial lakes, dams and sluices. In later periods the moat or water defences may be largely ornamental.


Historical use


North view of the fortress of Buhen in Ancient Egypt.

Some of the oldest evidence of moats has been uncovered around ancient Egyptian fortresses. One example is at Buhen, a fortress excavated in Nubia. Other evidence of ancient moats is found in the ruins of Babylon, and in reliefs from ancient Egypt, Assyria, and other cultures in the region.[1][2]


Moats were excavated around castles and fortifications as part of the defensive system as an obstacle immediately outside the walls. In suitable locations they might be filled with water. A moat made access to the walls difficult for siege weapons, such as siege towers and battering rams, which needed to be brought up against a wall to be effective. A water-filled moat made the practice of mining, digging tunnels under the fortifications in order to effect a collapse of the defences, very difficult as well.

The word was adapted in Middle English from the French motte "mound, hillock" and was first applied to the central mound on which a fortification was erected (see Motte and bailey), and then came to be applied to the excavated ring, a "dry moat". The term moat is also applied to natural formations reminiscent of the artificial structure, and to similar modern architectural features.


Ancient Nigeria - The Walls of Benin was a combination of ramparts and moats, called Iya, used as a defense of the capital Benin City in present-day Edo State of Nigeria. It was considered the largest man-made structure lengthwise, second only to the Great Wall of China and the largest earthwork in the world. With more recent work by Patrick Darling, it has been established as the largest man-made structure in the world, larger than Sungbo's Eredo. It enclosed 6,500 km² of community lands. Its length was over 16,000 km of earth boundaries. It was estimated that earliest construction began in 800 AD and continued into the mid 1400's.

The walls are built of a ditch and dike structure; the ditch dug to form an inner moat with the excavated earth used to form the exterior rampart.

The Benin Walls were ravaged by the British in 1897. Scattered pieces of the walls remain in Edo, with material being used by the locals for building purposes. The walls continue to be torn down for real estate developments.

The Walls of Benin City was the world's largest man-made structure.Fred Pearce wrote in New Scientist:

"They extend for some 16,000 kilometres in all, in a mosaic of more than 500 interconnected settlement boundaries. They cover 6,500 square kilometres and were all dug by the Edo people. In all, they are four times longer than the Great Wall of China, and consumed a hundred times more material than the Great Pyramid of Cheops. They took an estimated 150 million hours of digging to construct, and are perhaps the largest single archaeological phenomenon on the planet.


Map of the Tokyo Imperial Palace and surrounding Gardens showing the elaborate moat system

Japanese castles often have very elaborate moats, sometimes with many moats laid out in concentric circles around the castle and a host of different patterns engineered around the landscape. Japanese castles will have up to three of these concentric moats. The outer moat of Japanese castles typically protects other support buildings in addition to the castle.

As many Japanese castles have historically been a very central part of their respective city, the moats have provided a vital waterway to the city. Even in modern times, the moat system of the Tokyo Imperial Palace comprises a very active body of water, hosting everything from rental boats and fishing ponds to restaurants.[3]

Most modern Japanese castles have moats filled with water, but castles in the feudal period more commonly had 'dry moats' (karahori, 空堀), essentially a ditch. Even today, it is common for mountain Japanese castles to have dry moats.

Moats were also used in the Forbidden City and Xi'an in China; in Vellore in India; and in Southeast Asia, such as at Angkor Wat in Cambodia and Chiang Mai in Thailand.


While moats are commonly associated with European castles, they were also developed by North American Indians of the Mississippian culture as the outer defence of some fortified villages. The remains of a 16th-century moat are still visible at the Parkin Archeological State Park in eastern Arkansas. Further, the term moat was used to describe dry ditches surrounding forts built by colonials or Americans to protect important landmarks, harbors, or cities (see: Fort Jay on Governors Island).

The Mayans also used moats in the city of Becan.

Photo gallery

Modern uses

While moats are no longer a significant tool of warfare, they continue to serve as a defence against certain modern threats such as car bombs and armoured fighting vehicles. They also fill a variety of creative contemporary uses.

Installation security

The Catawba Nuclear Station, for instance, has been constructing a concrete moat around some of the plant (other sides of the plant are bordering a lake). The moat is a part of industry wide added precautions after the September 11, 2001 attacks. Related individuals have made a point to claim that the moat is not connected to the new MOX fuel that the plant will be receiving.[4]

"The concrete moat under construction at the station south of Charlotte has little to do with the utility's plans to start burning mixed-oxide fuel containing small amounts of weapons-grade plutonium next spring. Designed to prevent everything from passenger cars to military tanks from getting too close to the reactor, the moat is part of a post-Sept 11, 2001 security upgrade"[1]

Animal containment

Moats rather than fences separate animals from spectators in many modern zoo installations. Moats were first used in this way by Carl Hagenbeck at his Tierpark.[5] The structure, with a vertical outer retaining wall rising directly from the moat, is an extended usage of the ha-ha of English landscape gardening.

Zoological research

Researchers of jumping spiders, which have excellent vision and adaptable tactics,[6] built water-filled miniature moats, too wide for the spiders to jump all the way across. Some specimens were rewarded for jumping than then swimming, and others for swimming only. Portia fimbriata from Queensland generally succeeded, for whichever method they were rewarded.[7] When specimens from two different populations of Portia labiata were set the same task, members of one population worked out for whichever method they were rewarded, while members of the other continued to use whichever method they tried first and did not try to adapt.[8]

Border control

In 2004 plans were suggested for a two-mile moat across the southern border of the Gaza Strip to prevent tunnelling from Egyptian territory to the border town of Rafah.[9]

In 2008, city officials in Yuma, Arizona planned to dig out a two-mile stretch of a 180-hectare (440-acre) wetland known as Hunters Hole, to control immigrants coming from Mexico.[10]

Pest control in Bonsai

As a basic method of pest control in bonsai, a moat may be used to restrict access of crawling insects to the bonsai.

Lighting and ventilation

Dry moat at the James Farley Post Office in New York City.

A dry moat at the James Farley Post Office in New York City allows light and fresh air to reach the basement workspaces.

See also


  1. ^ Archaeology in Syria Tell Sabi Abyad, , article on Netherlands National Museum of Antiquities website
  2. ^ Oreddsen, Dag (November 2000). "Moats in Ancient Palestine". Almqvist & Wiksell International. 
  3. ^ "Imperial Palace moats illegally occupied by businesses". Japan Today. August 25, 2006. 
  4. ^ "Nuclear Power Plants to Continue MOX Program". Nuclear Threat Initiative. October 13, 2004. 
  5. ^ Rene S. Ebersole (November 2001). "The New Zoo". Audubon Magazine (National Audubon Society). Retrieved 2007-12-18. 
  6. ^ Harland, D.P., and Jackson, R.R. (2000). ""Eight-legged cats" and how they see: a review of recent research on jumping spiders (Araneae: Salticidae)" (PDF). Cimbebasia 16: 231–240. Retrieved 5 May 2011. 
  7. ^ Jackson, Robert R.; Chris M. Carter, Michael S. Tarsitano (2001). "Trial-and-error solving of a confinement problem by a jumping spider, Portia fimbriata". Behaviour (Leiden: Koninklijke Brill) 138 (10): 1215–1234. ISSN 0005-7959. JSTOR 4535886. 
  8. ^ Jackson, Robert R.; Fiona R. Cross, Chris M. Carter (2006). "Geographic Variation in a Spider’s Ability to Solve a Confinement Problem by Trial and Error". International Journal of Comparative Psychology 19: 282–296.;jsessionid=34833B994B69E2CA4DA97613EA34F531#page-1. Retrieved 8 June 2011. 
  9. ^ Urquhart, Conal (June 18, 2004). "Two-mile Gaza moat to foil tunnels to Egypt". London: The Guardian.,2763,1241836,00.html. Retrieved May 12, 2010. 
  10. ^ Glaister, Dan (March 14, 2008). "US city plans moat to keep out migrants". London: The Guardian. Retrieved May 12, 2010. 

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Look at other dictionaries:

  • Moat — Moat, n. [OF. mote hill, dike, bank, F. motte clod, turf: cf. Sp. & Pg. mota bank or mound of earth, It. motta clod, LL. mota, motta, a hill on which a fort is built, an eminence, a dike, Prov. G. mott bog earth heaped up; or perh. F. motte, and… …   The Collaborative International Dictionary of English

  • Moat — Moat, v. t. To surround with a moat. Dryden. [1913 Webster] …   The Collaborative International Dictionary of English

  • moat — (n.) mid 14c., from O.Fr. mote mound, hillock, embankment; castle built on a hill (12c.; Mod.Fr. motte), from M.L. mota mound, fortified height, of unknown origin, perhaps from Gaulish mutt, mutta. Sense shifted in Norman French from the castle… …   Etymology dictionary

  • moat — [mōt] n. [ME mote < OFr, orig., mound, embankment, prob. < Gmc * motta, heap of earth] a deep, broad ditch dug around a fortress or castle, and often filled with water, for protection against invasion vt. to surround with or as with a moat …   English World dictionary

  • moat — [məut US mout] n [Date: 1300 1400; : Old French; Origin: mote, motte small hill (on which a castle was built) ] 1.) a deep wide hole, usually filled with water, dug around a castle as a defence 2.) a deep wide hole dug around an area used for… …   Dictionary of contemporary English

  • moat — [ mout ] noun count a deep wide hole, usually filled with water, that surrounds a castle as protection against attack a. a similar hole used for preventing animals from escaping in a ZOO …   Usage of the words and phrases in modern English

  • Moat — Rare, le nom est surtout porté en Lorraine (54, 55). Sens obscur. On peut sans doute faire le rapprochement avec Moet, Moët, patronyme champenois lui aussi assez incertain. Peut être celui qui fait la moue (ancien français et dialecte champenois… …   Noms de famille

  • moat — [n] ditch canal, channel, fosse, gully, trench; concepts 509,513 …   New thesaurus

  • moat — ► NOUN ▪ a deep, wide defensive ditch surrounding a castle or town, typically filled with water. DERIVATIVES moated adjective. ORIGIN Old French mote mound …   English terms dictionary

  • MOAT — Meaning af a Tag MOAT ou Meaning Of A Tag est un système permettant de préciser la signification des tags utilisés pour catégoriser des contenus en les associant à l URI d une ressource. C est un projet qui a été créé par Alexandre Passant dans… …   Wikipédia en Français

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