Thomas Wentworth Peirce, railroad magnate, son of Andrew and Betsy (Wentworth) Peirce, was born on August 16, 1818, in Dover, New Hampshire. He first visited Texas as a youth while on his way home from Cuba, where he had spent the winter because of ill health. He worked with his father, who was in trade and navigation, until 1837, then went into business with his brother Andrew in Dover. In 1843 he established the house of Peirce and Bacon in Boston and subsequently built it into one of the more prominent mercantile firms in the northeast. His brother Andrew became a partner in 1851. The company's extensive southern trade focused especially on Texas, where the Peirces dealt in cotton, sugar, and hides. In 1852 Peirce opened a branch house of the business in Galveston. With Ebenezar B. Nichols as its representative, Peirce and Bacon ran a line of fifteen packet ships to transport Texas products to the East Coast and to Europe. Peirce's business successes made him a wealthy and powerful man and fostered his interest in railroad development in Texas. He owned a large sugar plantation at Arcola served by the Houston Tap and Brazoria Railroad, which connected with the state's first railroad, the Buffalo Bayou, Brazos and Colorado at Peirce (later Pierce) Junction and provided direct access to Buffalo Bayou steamboats at Harrisburg and the port of Houston. In 1857 he was the attorney for the Houston and Texas Central Railway Company as well as one of its directors. Peirce was also involved in the administration of the BBB&C before the Civil War. During the conflict the road foundered, and in 1867 contractor William Sledge acquired it on a judgment.
Peirce was one of a group of investors, including Jonathan Barrett of Boston and John Sealy of Galveston, who purchased the bankrupt road in January 1870 and immediately petitioned the legislature for a new charter, which was granted on July 27 of that year under the name Galveston, Harrisburg and San Antonio Railway Company. The new owners had a great deal of capital to invest and lost no time in reviving the dilapidated properties and equipment. In 1872 Barrett resigned as president of the GH&SA, very likely bought out by Peirce, who became the dominant figure in the affairs of the road thereafter. Pierce also served as president of the Galveston, Houston and Henderson Railroad in 1875 and 1876 and was a director for several years. The GH&SA reached San Antonio on February 5, 1877, connecting that city to the Gulf and to East Texas for the first time and spurring major growth. Included in the inaugural San Antonio train was Peirce's luxurious personal railroad car, the first in the state. Peirce organized an immigration bureau to locate settlers on the nearly 1.5 million acres granted to the GH&SA by the state of Texas along the railroad line, and also financially supported the establishment of towns and services along the route. In order to extend the Sunset Route, as the GH&SA was called, westward beyond San Antonio, Peirce allied his railroad and construction crews with C. P. Huntington's Southern Pacific, which was building eastward toward El Paso. On January 12, 1883, on the banks of the Pecos River 227 miles west of San Antonio, Peirce drove the silver spike that completed the long-awaited southern transcontinental rail line between California and New Orleans via Texas. In addition, Peirce completed a branch of the GH&SA to Eagle Pass on November 15, 1882, and, in partnership with Huntington, built an international rail bridge across the Rio Grande. In the 1880s Peirce sold his share of the GH&SA to Huntington and became interested in the Pan-American Railway Company, a road chartered in 1890 by Boston capital to run from Victoria, Texas, to Brazil. Only ten miles of rail were ever laid. Peirce also attended a meeting with U. S. Grant, Mexican president Porfirio Díaz, Jay Gould, and C. P. Huntington to discuss the establishment of a Mexican railway system. During this period Pierce joined with New York investors and the owners of the Colorado-based Denver and Rio Grande Western Railroad in the purchase of the 960,000-acre Corralitos Hacienda in Chihuahua, which exported its cattle to El Paso.
The Peirce family home was an estate at Topsfield, Massachusetts, to which Peirce returned every summer. A railroad siding beside the house accommodated his private car, a luxury that was increasingly necessary in his later years of failing health. After the death of his first wife, Mary Curtis, Peirce married Cornelia Cook of Galveston; they had a son and a daughter, both still quite young when Peirce died in October 1885, at Clifton Springs, New York. He was buried at Mount Auburn, Massachusetts. His railroad dealings in Texas earned him massive landholdings; at the time of his death he owned more than 700,000 acres of land in the state, and his estate was valued at more than $8 million. All his Texas properties were sold by his executors before his children came of age.