O'Connor, Dennis Martin (1839–1900)

By: Craig H. Roell

Type: Biography

Published: 1952

Updated: April 3, 2019

Dennis Martin O'Connor, cattleman, was born in Refugio County, Texas, on October 9, 1839, the eldest son of Mary (Fagan) O'Connor and "Texas Cattle King" Thomas O'Connor. He was educated at Ingleside, San Patricio County, until the outbreak of the Civil War. He enlisted in the Confederate army as a private in the Twenty-first Texas Cavalry and saw action in Kansas and Missouri. After the war he worked for a few years as a merchant but about 1870 joined his father in raising cattle. He also became associated with the banking firm of O'Connor and Sullivan in San Antonio. In 1887 he inherited most of his father's vast estate in Refugio, Aransas, Goliad, San Patricio, McMullen, and La Salle counties; the legacy of over 500,000 fenced acres and 100,000 cattle was valued at $4.5 million. Dennis O'Connor's main ranch of 180,000 acres was located in Victoria County, near Victoria, where he had built his residence in 1876. The home became a showplace of the locality. He experimented with improving cattle breeds and found that the longhorn crossed with the dark red Devon was best for rapid growth and quick fattening. In the 1880s O'Connor pioneered with his father the drilling of artesian wells to sustain cattle during drought. He imported what was probably the first rotary drilling equipment in Texas. Water drillers frequently struck oil, much to O'Connor's disappointment, since oil at the time had only a limited value, especially in comparison with water, and harmed valuable grazing land. Later, one of his sons developed on the ranch the Tomo'connor field, one of the world's largest and most productive oilfields.

O'Connor, who once served as a deputy United States marshal, was chosen by biographer Lewis E. Daniell to represent "a real live Texas `Cattle King'" for Types of Successful Men in Texas (1890). A multimillionaire known for his generosity, O'Connor helped improve the Rockport harbor in 1889, built for his ranchhands a chapel in which he installed an eighteenth-century bell that he had preserved from Nuestra Señora del Refugio Mission, and sponsored and equipped the Dennis M. O'Connor Guards, Second Regiment, Texas Volunteers, during the Spanish-American War. O'Connor contributed substantially to the Republican party. He presented President Benjamin Harrison a chair (now in the Harrison home museum) crafted of Texas longhorns by Charles Puppe and gave President William McKinley a mounted longhorn head ornamented with diamonds, its horns being the longest known in Texas at the time. In 1897 O'Connor became a charter member and the first life member of the Texas State Historical Association, to which he also contributed funds. O'Connor married Mary Virginia Drake, a direct descendant of Sir Frances Drake, in Victoria on April 16, 1868. The couple had four children, including Thomas, whose wife, Kathryn Stoner O'Connor , brought about the restoration of La Bahía Presidio at Goliad in the 1960s. In August 1900 O'Connor started to New York for medical treatment, but his private car was sidetracked at Bryan, where he died on September 18, 1900.

Lewis E. Daniell, Personnel of the Texas State Government, with Sketches of Representative Men of Texas (Austin: City Printing, 1887; 3d ed., San Antonio: Maverick, 1892). Roy Grimes, ed., 300 Years in Victoria County (Victoria, Texas: Victoria Advocate, 1968; rpt., Austin: Nortex, 1985). J. Marvin Hunter, Trail Drivers of Texas (2 vols., San Antonio: Jackson Printing, 1920, 1923; 4th ed., Austin: University of Texas Press, 1985). Hobart Huson, Refugio: A Comprehensive History of Refugio County from Aboriginal Times to 1953 (2 vols., Woodsboro, Texas: Rooke Foundation, 1953, 1955).

  • Ranching and Cowboys
  • Ranchers and Cattlemen

The following, adapted from the Chicago Manual of Style, 15th edition, is the preferred citation for this entry.

Craig H. Roell, “O'Connor, Dennis Martin,” Handbook of Texas Online, accessed May 24, 2022, https://www.tshaonline.org/handbook/entries/oconnor-dennis-martin.

Published by the Texas State Historical Association.

April 3, 2019