Thomas Mathias Lenihan (August 12, 1844 – December 15, 1901) was an Irish-born American prelate of the Catholic Church who served as bishop of the Diocese of Cheyenne in Wyoming from 1896 until his death in 1901.

[3] At age 12, Lenihan entered St. Thomas Seminary in Bardstown, Kentucky, where he received his classical education.

[6][7] In civic affairs, Lenihan was appointed to the state's Russian famine relief committee by Governor Horace Boies.

[9] In 1893, it was reported that the Vatican was planning to erect a new Diocese of Sioux City and appoint Lenihan as bishop.

[11] At first there was some confusion in the press, who mistakenly believed that Reverend Bartholomew C. Lenihan, his cousin and the vicar general of the Archdiocese of Dubuque, had been appointed.

[14] When Lenihan arrived in Cheyenne in 1897, the diocese contained eight priests, nine churches, and one parochial school for 3,000 Catholics.