SAN ANTONIO -- We Texans take pride in our state history. In fact, all 254 counties have historical markers along state highways detailing events or locations for which Texans can be proud.

But did you know that these markers are made in San Antonio?

Not many businesses can say they've survived 100 years, but The Southwell Company is celebrating an even bigger milestone.

This year marks 150 years of business in the Alamo City.

"We started by making stencils for the cotton and wool trade here in Texas," said Scott Southwell, who co-owns The Southwell Company with his brother, Billy.

Since 1866, before Office Depot and Staples existed, there was The Southwell Company.

"We were one of the biggest stamp manufacturers in the United States," Southwell noted.

It's a family-owned business, now in its fourth generation, primarily known for making historical markers.

"We do them in Delaware, Georgia, we just got a contract to make all the official markers in Kentucky," Southwell said. "We're making one right now for the Louisville Slugger Bat Company."

Each marker takes up to six weeks to make.

Since the company started making historical markers in the 1960's, they've completed over 16,000 official historical markers for Texas alone.

"[The TV presenter] is standing in front of [the historical marker] on national TV and they're talking about the agency or they're talking about whatever's behind the sign, and we can say, 'Hey! We made that!' That's really, really gratifying," Southwell said.

They use a technique thousands of years old to mold the marker's impression into a special, secret sand recipe.

"It's old tech, old school and high tech," Southwell explained. "These are made to last. The paint might fade, but the metal is going to be there forever."

The Southwell Company's clients include President Jimmy Carter, Janice Joplin, the University of Texas at Austin and the NSA.

"We've made signage in Mexico, we've made signage in Arabic at some of the air bases," Southwell said.

The Southwell Company is also their own client.

After a request by the Texas Historical Commission, the company made its own 150-year plaque, presented to them by San Antonio billionaire Red McCombs.

"This old City of San Antonio and this old company is still right abreast of everything that is going on and right on top of everything that's going on," McCombs said.

McCombs, a childhood best friend of former owner Bill Southwell Jr., presented the company with the special plaque on Tuesday afternoon at the San Antonio Chamber of Commerce.

"To be by him is the biggest honor I've ever had," said Bill Southwell of McCombs. "He is one of my dearest friends."

To view the presentation by Red McCombs and the San Antonio Chamber of Commerce to The Southwell Company watch below.

For more information on how the company's plaques, historical markers, and signage is made, catch KENS 5's Made in San Antonio segment Friday morning.