The Memorial Hall on Leek Road, west of the Wheel Public House was built in 1920 by the village stonemasons from stone hewn from the village quarry, as a memorial to the men of Longsdon who perished in the 1914-18 war. The names of all who perished are listed on a plaque inside the hall.
A second plaque with the names of all who perished in the 1939-45 war was added after the war.
During the 1939-45 conflict a Home Guard unit was set up in the village and practiced defensive drill in the Memorial Hall and marching practice on the grass at the back of the Hall. The unit consisted of males from the village who worked in what were called reserved occupations, and men who were not fit enough to join the armed forces. Farmers, people who worked in the service industry and on manufacture of munitions, were classified as reserved occupations. The function of the Home Guard was to defend the village in the event of an enemy invasion. The Home Guard were not issued with weapons so they had to improvise with whatever they had; farmers would have shot guns and the other members would have axes and pitch forks or anything that they could inflict injury on the enemy, if they got near enough.

For the six years of the conflict, members of the Home Guard manned their station throughout the night and were still expected to turn up for work the following morning.