The Wilmarth Foundation is an organization based in Arkham, MA dedicated to combating the Great Old Ones with hundreds of agents and connections all over the world.
During the 1960s they organised both the Great Britain Project and the American Project to drive out the Cthulhu Cycle Deities from their respective countries. The Great Britain Project was particularly successful, clearing the island of subterranean monstrosities and resulting in the death of the creature referred to as Cgfthgnm'o'th.