The Roman Catholic Diocese of Lead in South Dakota (Dioecesis Leadensis in Latin) was created on August 4, 1902 by Pope Leo XIII. The diocese covered the portion of South Dakota west of the Missouri River, a region sometimes known as West River. On August 1, 1930, the name of the diocese was changed to the Roman Catholic Diocese of Rapid City.
In 1995, the Diocese of Lead was restored as a titular see with Bishop Joseph Perry being the first one to receive the titular see.
References
Ancient Diocese of Lead Wikipedia(Text) CC BY-SA