Fort Devens is not a city, but rather a former military installation located in the towns of Ayer and Shirley in Massachusetts, United States. Originally established as a military base in 1917, it was used for a variety of purposes over the years, including training and support for various military units. In 1996, Fort Devens was closed as an active military installation and since then has been repurposed as a multi-use facility for a variety of public and private entities.