A site along the U.S.-Mexico border where enslaved people passed while using the Underground Railroad into Mexico is getting important recognition from the U.S. National Park Service.

Why it matters: Historians believe that between 4,000 to 10,000 enslaved Black people may have migrated south, yet there's been little documentation and mentions in history books about the Underground Railroad to Mexico.

Zoom in: The NPS announced last month that its National Underground Railroad Network to Freedom program will now include the Jackson Ranch Church and Martin Jackson Cemetery, located in San Juan, Texas, which once served as a gateway to Mexico for enslaved people seeking freedom.

• The NPS network consists of more than 700 sites, programs, and facilities with a verifiable connection to the Underground Railroad. Most sites are connected to the more well-known Underground Railroad of the North, an organized system that helped enslaved people escape to Canada.
• The Jackson site is one of 19 new listings added this year.
• The Underground Railroad to Mexico was a loosely organized path for enslaved Black people in Texas, Louisiana, Oklahoma and Alabama to escape bondage by fleeing south.

What they're saying: Including the Jackson site in the NPS network is an important step in eventually getting a historic site designation, Roseann Bacha-Garza, a program manager for the University of Texas Rio Grande Valley's Community Historical Archaeology Project with Schools, tells Axios.

Flashback: The Jackson site is part of a ranch started by Nathaniel Jackson, a white man from Alabama, and his wife, Matilda Hicks, a Black woman who had been enslaved. Hicks and Jackson were childhood sweethearts.

• According to historians, as an adult Jackson later purchased the freedom of Matilda Hicks and her children and moved to South Texas before the U.S. Civil War.
• There, they led a covert operation that helped enslaved Black people cross into Mexico.

Between the lines: The Jackson site sits south of a border wall that was built during the administration of former President Trump despite protests about the area's historical significance. The site also is north of the Rio Grande, which serves as the literal border between Mexico and the U.S., making visiting the site challenging.

The big picture: The Jackson ranch was located next to another owned by Silvia Hector Webber — dubbed by some historians as the "Harriet Tubman" of the Underground Railroad to Mexico — and her husband, John, who was white.

• The Webbers built a ferry landing on their property to help enslaved escapees move along the Colorado River toward Mexico, says Ohio State history professor María Esther Hammack.
• Hammack says the Jackson site is also an essential part of this history.

What's next: Bacha-Garza says advocates want to make it more accessible to visit and transform it into a pilgrimage site like the Freedom Monument Sculpture Park and National Monument to Freedom in Montgomery, Alabama.

• Bacha-Garza adds that advocates will seek grants to print brochures and maps that give visitors more history of the Jackson ranch.
• "Working with family members to capture and preserve this very valuable history means a great deal to me because I've made such good friends with many of the family members."

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