A ditch and earth bank at Old Sarum, near Salisbury in England, dating from the Iron Age.
Ditch of Valletta, which was built between 1566 and the 1570s.

In military engineering, a ditch is an obstacle designed to slow down or break up an attacking force, while a trench is intended to provide cover to the defenders. In military fortifications the side of a ditch farthest from the enemy and closest to the next line of defence is known as the scarp while the side of a ditch closest to the enemy is known as the counterscarp.


In early fortifications, ditches were often used in combination with ramparts to slow down the enemy whilst defensive fire could be brought to bear from the relative protection afforded by the rampart and possibly the palisade. In medieval fortification, a ditch was often constructed in front of a defensive wall to hinder mining and escalade activities from an attacker. When filled with water, such a defensive ditch is called a moat. However, moats may also be dry.

Later star forts designed by military engineers like Vauban, comprised elaborate networks of ditches and parapets, carefully calculated so that the soil for the raised earthworks was provided, as nearly as possible, entirely by the excavations whilst also maximising defensive firepower.

Today ditches are obsolescent as an anti-personnel obstacle, but are still often used as anti-vehicle obstacles (see also berm).

A fence concealed in a ditch is called a ha-ha.

Elements of a ditch in an artillery fortification (16th to 19th centuries)

A section through the ditch and rampart of a typical early modern artillery fortification (16th to 19th centuries). The elements are: a) glacis, b) banquette, c) covered way or covertway d) counterscarp, e) ditch (dry), f) cunette, g) scarp or escarp, h) faussebraye, i) chemin de ronde, j) rampart (exterior slope), k) parapet, m) terreplein.

See also: List of established military terms § Engineering

See also


  1. ^ Hogg, Ian V (1975) Fortress: A History of Military Defence, Macdonald and Jane's, ISBN 0-356-08122-2 (pp. 54-56)
  2. ^ a b "A Glossary of Victorian Military Terms". www.victorianforts.co.uk. Victorian Forts and Artillery. Archived from the original on 4 March 2016. Retrieved 29 May 2016.
  3. ^ Lepage, Jean-Denis G G (2010), Vauban and the French Military Under Louis XIV: An Illustrated History of Fortifications and Strategies, MacFarland & Company Inc, ISBN 978-0-7864-4401-4 (pp. 90-92)