The rivalry seems to know no bounds. When a developer decided to build a convention center in one town, the other side made plans to erect one, too - even though the two facilities will be just a few miles apart.
"It can kind of be harmless from the perspective of the football game or just some petty bickering," said geographer Michael Glass, who lectures about urban studies at the University of Pittsburgh. "But when it comes to putting tax dollars on the line by trying to have competing convention centers, you've got to ask yourself, 'Has it gone too far?' "
The two Texarkanas - with names forged from Texas, Arkansas, and nearby Louisiana - have managed to work together over the years, even though they function as separate cities. They have their own police forces and fire departments, but they share an airport, a federal building, and wastewater treatment plants. Residents of both towns cross into the other every day for work, school, and shopping.
Of course, the two cities have had disagreements in the past. "But they always worked them out in fairly short order," said Bill King, the water utility's executive director.
That began to change a few years ago. Personalities clashed after former Superintendent Larry Sullivan took over as Texas' city manager in 2007 and rubbed folks on the Arkansas side the wrong way with a leadership style some saw as controlling.
The current mayor, N. Wayne Smith, said he won't even sit down with Sullivan.
"If no one's willing to sit down and talk with you about how to solve a problem, it's next to impossible to be able to come to any kind of agreement," said Sullivan, who is retiring at the end of the month.
As if to fit a stereotype, the Texas side is slightly bigger, with about 36,000 residents, compared with 30,000 on the Arkansas side. The Texas city also is more developed, offering strip malls, chain restaurants, and car dealerships - advantages that lead some people on the Lone Star side to downplay the competition with their Arkansas neighbors, much as an older sister would insist there's no rivalry with her younger sibling.
"I don't see the competitiveness of the Arkansas side," said Skipper Lumpkin, a retired first-grade teacher on the Texas side. "Texas' side is the one that's got all the shops and all. About all Arkansas' side has is Wal-Mart."
Texarkana, Ark., also has something of an inferiority complex. The Texas side has a Starbucks and Target.
"People perceive that Arkansas is the stepchild of the Texas side," Smith said.
Smith and others on the Arkansas side want to change that. After a developer chose to build a convention center on the Texas side, which chipped in millions of dollars toward the project, leaders on the Arkansas side decided they weren't going to be outdone.
They found a different developer willing to construct another multimillion-dollar convention center. And they raised the ante with Texas by including a water park in the hopes of attracting tourists to a region not exactly known as a vacation destination.
"Whatever it is I can do, I'm going to do that to make sure that Texarkana, Ark., gets the tourism dollars," Smith said. "If that means that we're competing heads up with Texas, then we're competing heads up."
Smith has met with the Texas side's new mayor, Bob Bruggeman, who says he wants to improve the cities' relationship. "My campaign slogan was: Unite Texarkana," he said.
That's a tall order since the cities have been locked in a legal battle for years, quibbling over the water utility that has served them both for decades.
Texas, where a water tower proclaims "Texarkana is twice as nice," argued the utility really is a department of its city. Arkansas, not wanting to concede any ground, disagreed.
A federal judge in Arkansas scolded the cities recently for what he called political posturing. The back-and-forth bickering likely will mean a higher price tag on a stalled multimillion-dollar upgrade for a wastewater treatment plant.