Historic Discovery Confirms the Quarry That Supplied Limestone for The Alamo

A significant historical discovery has confirmed the exact quarry that provided the limestone used to build he Alamo, solving a long-standing mystery about the origins of one of America’s most iconic landmarks.
 
The news was first revealed exclusively on Good Morning America earlier today during a special live segment from the Alamo’s annual Dawn Ceremony, marking the 189th anniversary of the Battle of the Alamo.
 
During excavation for San Antonio Zoo’s new gorilla habitat Congo Falls and The Ralston (event center), large amounts of limestone were unearthed, prompting further investigation. Through extensive geological testing and historical research conducted by Highbridge Materials Consulting, Inc., experts have now verified that the quarry—located on the far west side of the Zoo—was a primary source of stone used in the 1700s to build the Alamo Church and other historic structures in San Antonio.
 
“This discovery deepens our understanding of the Alamo’s origins and reinforces the strong historic ties between our city’s landmarks,” said Dr. Kate Rogers, Executive Director of the Alamo Trust, Inc. “For the first time, we can say with confidence that this quarry, now part of the San Antonio Zoo, supplied the materials that built one of the most recognized historical sites in the United States.”
 
Originally established in 1718, Mission San Antonio de Valero, later known as the Alamo, was relocated to its current site in 1724. It was constructed using locally sourced limestone. Confirming this quarry’s location provides an unprecedented link to the materials that shaped San Antonio’s historic built environment.
 
“The San Antonio Zoo, which has been a part of our community for over a century, is honored to play a role in uncovering this important piece of Texas and world history,” said Tim Morrow, President and CEO of the San Antonio Zoo. “This is an incredible example of how history continues to reveal itself, even in the middle of progress. Limestone from this location helped shaped San Antonio and Texas.”
 
To verify the connection, Highbridge Materials Consulting, Inc. conducted a comprehensive geological and material analysis. Their team compared limestone samples from the Alamo’s structure to the layers excavated at the Zoo site, confirming that the geological composition matches the materials used in the original construction of the Alamo Church.
 
This revelation comes at a pivotal moment, as the Alamo undergoes a $550 million redevelopment set for completion in 2027. The project includes a state-of-the-art Visitor Center & Museum, which will tell the full 300-year history of the Alamo and showcase new research like this discovery.
 
“This finding further strengthens our commitment to ensuring that the Alamo’s 300-year story is told with historical accuracy and depth,” added Dr. Rogers.

Alamo Trust, Inc. (ATI) is a 501c3 nonprofit organization that oversees the daily operations at the Alamo and the implementation of the Alamo Plan. Located in the heart of San Antonio, the Alamo stands as the Shrine of Texas Liberty. More than 1.6 million visitors travel to the site each year, making it the #1 most visited destination in the State of Texas. The 300-year history of the Alamo is world-renowned and represents the core of Texas’ identity today. In 1960, the Alamo was designated a United States National Historic Landmark, and in 2015, it became part of the Lone Star State's only UNESCO World Heritage Site. Witness living history, experience authentic artifacts, and explore an iconic landmark that shaped the country. Visit theAlamo.org.

San Antonio Zoo®, operating since 1914, is a nonprofit zoological facility committed to securing a future for wildlife. Through its passion and expertise in animal care, conservation, and education, the zoo's mission is to inspire its community to love, engage with, act for and protect animals and the places they live. The zoo welcomes more than a million visitors each year and is open year-round. San Antonio Zoo operates the largest nature based preschool in the country, Will Smith Zoo School, the Center for Conservation and Research, and Kiddie Park. San Antonio Zoo is accredited by the Association of Zoos and Aquariums, the Zoological Association of America, and Humane Certified by American Humane.