Thomas C. Power was born in Dubuque, Iowa, May 22, 1829, the son of Irish immigrants, Michael Walsh Power and Catherine McLeer Power. He was raised on the family farm near Dubuque. The eldest of four children, Power worked on the farm while completing basic education courses offered in area schools. In his teens, Power attended Sissinawa Mound College, in Wisconsin, where he studied science and engineering. After three years of college course work, but without graduating, he returned to Iowa and taught in rural schools near Peru, Iowa, during the years 1858-1860. In 1860, Thomas Power accepted a job with a survey party for the federal government and spent the next four years surveying for government and private firms in the Dakotas, Nebraska, Kansas and eastern Montana. In 1865, he settled in Nebraska, first working as a carpenter, and, in 1865, he became a minor partner in a wholesale merchandising firm supplying several frontier areas.

This investment, and his familiarity with the West, led him, in the following year, to locate at Fort Benton, Montana, head of navigation on the Upper Missouri. With the stock of goods he brought with him, he opened a general mercantile firm in the spring of 1867. His younger brother, John Walsh Power (1844-1901), followed later that spring with more inventory, and Power's initial company, T. C. Power and Brother, was formed.

T. C. Power's firm was ideally located. It traded with residents of the locality, the military garrison, and Indian tribes of the region. As head of navigation on the Missouri, Fort Benton also offered unique advantages of supply and served as the hub of a freighting network to the towns and camps of the isolated Territory. Power rapidly exploited his situation and, in 1868, began supplementary overland freighting operations while expanding the range and quantity of his merchandise.

T. C. Power and Brother and the other large Fort Benton firm, I. G. Baker and Company, dominated trade and freighting on the northern plains by the mid 1870's. A significant portion of the business of these firms was in the fur and hide trade with Indians of the region and other hunters, an involvement that coincided with the period of slaughter of the northern buffalo herd. The hide trade, and, later, buffalo bones made up many of the down river cargos in the 1870's and early 1880's.

The rapid expansion of the Power and Baker firms caused them to invest in the construction of the river steamer "Benton", to supply goods for their operations and to carry gold, silver, hides, and other products down river. This investment, in 1874, resulted in the formation of the Fort Benton Transportation Company. In subsequent years other steamboats were built or purchased to expand this facet of the trade. In the late 1870's, Power purchased Baker's interest in the steamer line and continued its expansion until the firm dominated the Upper Missouri commerce in the years remaining before railroads reached the region and effectively ended river transportation. As an adjunct to his steamer and freighting interests, Power, in 1879, formed the first of several stagecoach lines which served much of northern and central Montana and, eventually, linked with the transcontinental Northern Pacific Railroad at Billings.

While retaining his investments in the Fort Benton area, in 1878, T. C. Power settled permanently in Helena, by then Territorial capital, and later State capital, and rapidly emerging as the focus of Montana's finance and trade. Having centered his business interests at Helena, Power became active in the capital's economic, political, and social life. He maintained several commercial firms, built and operated the American National Bank, and speculated in real estate and regional mining companies.

T. C. Power's entrepreneurial interests were extremely broad. He founded or invested in over ninety-five companies in the course of his active career. During the period 1880-1920, in addition to major interests in merchandising and transportation, he invested in cattle and sheep ranching; real estate throughout the northwest; lumbering; coal mining; electric power generation; hotels; automobile distributing; military and reservation supply; agricultural implement sales; banking; grain milling; municipal water supply; metals mining; oil; and irrigation.

In addition to the T. C. Power Company with headquarters in the Power Block in Helena, companies in which Power invested included the Judith Mercantile and Cattle Company in Fergus County, organized as the Judith Cattle Company in the summer of 1878 by T. C. Power and Brother, J.H. Knight, and H.P. Brooks; T. C. Power and Brother Lumber; Power Mercantile; Power Motor Car Company in Helena, Montana; the Sun River Stock and Land Company; the N.S. Ranch; Crown Butte Ranch; the PN Ranch with G.R. Norris; Escallier Sheep Company; Power Implement Company in Bozeman, Montana; Power-Morgan Company in Choteau, Montana; Power-Wilson Company Garage; Belgrade Company, Ltd.; and the Trident Store Company.

An interest in politics paralleled Power's diverse business career. A lifelong Republican, he was an active supporter of the Territorial and State party, as well as contributing to and involving himself in national party affairs. He served as a delegate to the abortive 1884 Constitutional Convention, but chose not to run for the 1889 Convention which resulted in Montana's statehood. Power was defeated in the first state gubernatorial election, in 1889, by Joseph K. Toole, the Democratic candidate.

In 1890, Power was selected by the divided First State Legislative Assembly as one of four senators, two from each party, to fill Montana's two seats in the nation's upper house. Power and the other Republican chosen, Wilbur Fisk Sanders, were seated by the Republican-controlled U.S. Senate over the bitter opposition of the Democratic contenders. Power's service in the Senate, 1890-1895, was creditable, with concentration on the State's major interests: the free coinage of silver; irrigation; the disposal of the public domain; and the wool tariff. T. C. Power's one term in the Senate ended his active involvement in politics.

Thomas C. Power married Mary G. (Molly) Flanagan at Dubuque, Iowa, in 1867, just prior to traveling to Montana. The couple had one son, Charles Benton Power. Mary Flanagan Power died in 1920. T. C. Power, still in active control of his varied financial interests, died at Helena, Montana, March 16, 1923.

In addition to Thomas C. Power and John Walsh Power, Michael Walsh Power and Catherine McLeer Power had two daughters who also moved to Montana from their native Iowa. Their older daughter, Sarah Power (1848-1935), remained unmarried. Their younger daughter, Josephine Power (1856-1904), married Thomas L. Martin. Josephine Power Martin and Thomas L. Martin had one son, Leo Martin, born in 1888. He became a Jesuit priest. John Walsh Power married Nellie T. Kelly in 1883. They had one son, John Merlin Power (1888-1940). His mother died in 1888 and his father in 1901. John Merlin Power was raised by Aunt Sarah Power, T. C. Power's sister. She also raised Leo Martin after his parents died.

Charles Benton Power, Sr. was born at Dubuque, Iowa, November 9, 1868. His early life was spent at Fort Benton, Montana, center of his father's financial interests. He moved to Helena with his family in 1878. There he completed his early education in the public schools. In 1888, C. B. Power received a Bachelor of Arts degree from Georgetown College, Washington, D.C., and later completed a supplemental Bachelors degree and a law degree at Columbia University, in 1891 and 1893.

C. B. Power returned to Helena, Montana, after completion of his education and entered the practice of law. He joined his father, in 1895, in the management of the Power business interests in Montana and the northwest. As an educated and handsome single gentleman, C. B. Power was active and popular in Helena society. In 1923, after his father's death, Power succeeded to ownership and operation of the remaining firms. During his business career, C. B. Power's interests remained primarily in merchandising and real estate, but he also invested in oil, hotels, agriculture and mining.

C. B. Power married Mabel Lamey Larson, niece of Margaret Moran Larson, in 1902. Mabel Agnes Lamey was adopted by Peter Larson (1849-1907) and his wife, Margaret Moran Larson (circa 1860-1924). C. B. Power and Mabel Larson Power had three children: Margaret Mary (1903-1954), who married twice and became the Countess of Carrick; Charles Benton, Jr., (1906-1931) also a graduate of Georgetown College; and Jane Elizabeth (1911-1988). Jane Power married Thomas D. Tobin in 1939. The couple had three children, Judith, Benton, and Jane.

Mabel Power died in 1918. In 1944, C. B. Power was remarried to Pauline Ely. He died in Helena, November 15, 1953, and Pauline died in 1971. Jane Power Tobin died in Helena in 1988.

Residences occupied by The T. C. Power family in Helena include 106 Benton, 432 Dearborn and 604 Harrison. The C. B. Power family resided at 309 N. Ewing, 642 Dearborn, later occupied by the Jane Power Tobin family.