The Fort Harrison Hotel has served as the main building of the Flag Land Base, the Church of Scientology's campus in Clearwater, Florida. It is owned and operated by the Flag Service Organization.

The Church of Scientology is a group of interconnected corporate entities and other organizations devoted to the practice, administration and dissemination of Scientology, which is variously defined as a cult, a business, or a new religious movement. The movement has been the subject of a number of controversies, and the Church of Scientology has been described by government inquiries, international parliamentary bodies, scholars, law lords, and numerous superior court judgements as both a dangerous cult and a manipulative profit-making business. In 1979, several executives of the organization were convicted and imprisoned for multiple offenses by a U.S. Federal Court. The Church of Scientology itself was convicted of fraud by a French court in 2009, a decision upheld by the supreme Court of Cassation in 2013. The German government classifies Scientology as an unconstitutional sect. In France, it has been classified as a dangerous cult. In some countries, it has attained legal recognition as a religion.