Impressment, commonly known as press-ganging, is a practice where people are forced to serve on ships or in the military. The British navy is notorious for its history of impressment, which started in the 13th century and continued up until the mid 1800s. Individuals who were impressed were seized from places like taverns and restaurants in port towns and dragged on board a ship to serve as sailors. Impressment into the military was less common, but still occurred, especially when soldiers were needed for remote conflicts.

Conditions in the navy and military of most European nations were very difficult through the 1800s. Sailors especially contended with extreme living conditions which included exposure to dangerous diseases, limited food, brutal punishment, and long trips away from home. As a result, voluntary enlistment sometimes did not supply enough manpower. A press gang of particularly strong sailors would be assembled to capture able sea men to fill the crew complement.

Any man between the ages of 18-55 was at risk for impressment, whether or not he was a sailor. Skilled sailors were preferred, of course, and some press gangs would wait on the docks around incoming ships to grab sailors who had just been discharged. Any individual who was in decent physical condition could be swept up by a press gang, and while impressment was only supposed to apply to British citizens, others were impressed as well. At sea, British officers could stop ships from other nations to look for escapees from the Navy, and they often seized this opportunity to impress sailors from other nations as well.

The British Navy was not the only national military to increase manpower with impressment: the Dutch and French practiced it as well. Mercantile ships would also often use press gangs to fulfill their crew, especially ships used in the slave trade. Sailors tried to avoid slave ships because of the brutal conditions on board, and the men who volunteered to serve on slavers were usually in desperate situations.

A press gang would usually be headed by an officer of the ship, who would select a crew of strong and ruthless sailors to help him capture men. Initially, a press gang might approach a man with an offer of employment, in an attempt to get him to come along willingly. If this measure failed, the press gang would use brute force to capture the sailor, bringing him on board the ship and not allowing him up on the decks until the ship had sailed, in order to minimize escapes.

When military conscription began to be more widespread, impressment fell out of favor. It was sometimes used to enforce conscription, but more frequently it appeared in the form of a threat. Young men who wanted to evade conscription would send men in their place to avoid the appearance of a press gang: the military was more concerned with numbers of conscripts than it was with their identities. By the 1800s, many nations had outlawed impressment as an unlawful and morally questionable activity.