Frank Lloyd Wright’s spiritual formation influenced by Welsh Unitarianism and his lifelong interest in spirituality were far more dynamic than has been previously appreciated. This dissertation examines how Wright’s spirituality caused him to interpret not only religious architecture, such as churches and synagogues, but also the genres of residential, commercial, and civic architecture as holding the potential for becoming sacred spaces. Sacrality, in the context of creating of sacred spaces, depended on a proper understanding of the relationship between God, nature, and organic architecture for Wright. Wright’s spirituality provided a framework for exploring hierotopy, or the creation of sacred space, across divergent genres of architecture and stylistic changes throughout his architectural career.