Austin and San Antonio: So happy together?

Chances are San Antonio and Austin would never hook up on Tinder.

And if they did somehow wind up on a dinner date, Austin would spend the night alternately flirting with the server, talking about its superinteresting work and answering text messages. San Antonio would fill the frequent gaps in conversation with details of how former lovers trampled its yearning heart.

But it would be a different story if a professional matchmaker took matters in hand — someone with a sharp eye, to whom the potential for love is nice but secondary to a union of complementary interests.

And there are plenty of those between San Antonio and Austin. So many, in fact, that a competent matchmaker would make quick work of it.

It starts with population growth.

A fresh batch of numbers from the Census Bureau confirms the two cities are rapidly gravitating toward one another, whether or not their policymakers are aware of it.

San Antonio was the thirdfastest-growing big city in the U.S. between 2010 and 2019, based on raw numbers. It added 221,000 people, bringing its population to 1.5 million. Austin came in at No. 5. It grew by 177,000 in the same period, ending with a population of 979,000.

Even more remarkable was the explosive growth in their metro areas, in the smaller cities within San Antonio’s and Austin’s orbits.

Based on percentage increase, New Braunfels was the third-fastest-growing city, beefing up its population by a stunning 56.4 percent. Cedar Park, northwest of Austin, was No. 7 on the list, Round Rock No. 13.

Rogelio Sáenz, a demographer and professor at the University of Texas at San Antonio, said the I-35 corridor