Photo of Brien O'Connor Dunn
Brien O'Connor Dunn

Fennessey Ranch is part of the vast O’Connor family land empire in South Texas. In 1834, fifteen-year-old Thomas O’Connor came to South Texas from County Wexford, Ireland. In a fortune of fate, Thomas’s uncle, James Power, was an empresario, entrepreneurs who operated as land agents for the Republic of Mexico to bring in settlers who would develop the country’s unpopulated northern reaches. In exchange, the settlers would receive title to land. Thomas’s land grant was for 4,428 acres. He received an additional 1,280 acres as a reward for military service on behalf of the Texas Republic (he fought at the Battle of San Jacinto and signed the Goliad Declaration of Independence). Thomas was one of the first Texans to fence his land, along with Richard King and Mifflin Kenedy (founders of the King Ranch). At the time of his death in 1887, Thomas had accrued more than 500,000 acres and an estate worth about $4.5 million – reportedly the largest individual land and cattle owner in Texas. Thomas’s descendants acquired additional land, culminating in 750,000 acres.  


Brien O’Connor Dunn, a sixth generation Texan and descendant of Thomas O’Connor, created and pioneered conservation projects on the Fennessey Ranch. He was awarded the 1992 Outstanding Wildlife Conservationist award from the Copano Bay Soil and Water Conservation District, the 1997 National Wetland Award for Land Stewardship and Development from the Environmental Law Institute in Washington D.C., the 2006 Conservation and Environmental Stewardship Award from the Coastal Bend Bays Foundation, and the 2008-2009 Outstanding Lone Star Land Steward Award from Texas Parks and Wildlife. Brien passed away in 2016. The Ranch is now owned by the Brien O’Connor Dunn estate.


Sally Crofutt was Brien’s ranch manager for over 30 years, and together they developed and coordinated the Ranch’s conservation efforts. Sally was a member of the Mission-Aransas Reserve Advisory Board from 2009-2020.


Under a new agreement in 2020, the management of the Ranch was taken over by the Mission-Aransas National Estuarine Research Reserve when Sally retired. This agreement, the conservation easement, and the Fennessey Ranch Management Plan ensure proper implementation of land management practices, as well as access for research and educational opportunities.