Choke point

In military strategy, a choke point (or chokepoint) is a geographical feature on land such as a valley, defile or a bridge or at sea such as a strait, which an armed force is forced to pass, sometimes on a substantially narrower front and therefore greatly decreasing its combat power, to reach its objective. A choke point can allow a numerically inferior defending force to thwart a larger opponent if the attacker cannot bring superior numbers to bear.

Some historical examples of the tactical use of choke points are King Leonidas I's defense of the Pass of Thermopylae during an invasion led by Xerxes I of Persia, the Battle Of Stamford Bridge in which Harold Godwinson defeated Harald Hardrada, William Wallace's victory over the English at the Battle of Stirling Bridge (Wallace had around 2,300 men against the English army of about 9,000 to 12,000 men and the bridge collapsed during the battle) and the Battle of Agincourt in which Henry V of England decisively defeated the French when they were forced to attack his smaller army through a narrow gap in the Agincourt Woods.

It was the suitability of the Caribbean as a chokepoint that attracted pirates and buccaneers during the 17th century. The Spanish treasure fleets leaving the Americas would need to pass there to pick up the strong, prevailing, westerly winds that would take them back to Spain.

The most important naval choke points were first identified by Fisher in his defence of continued British colonialism (important colonies in parentheses):

...
Wikipedia