SUGAR LAND, Tex. — Nearly 700 miles from the El Paso Walmart where the suspect in the killing of 22 people on Saturday denounced a “Hispanic invasion,” Rish Oberoi, a candidate for state representative, gestured toward a bustling dining room in a popular Vietnamese restaurant and marveled at the diversity of this Houston suburb.

“You’ve got every ethnicity,” Mr. Oberoi, the son of Indian immigrants, said of the lunchtime rush on Monday. “And that’s standard for Sugar Land.” He was not overstating the case.

The residents in this county speak at least 118 languages, elected an Indian immigrant as their leader in 2018 and elevated the first Muslim to the Sugar Land City Council this year. Once represented by Tom DeLay, the hard-line House majority leader known as the Hammer for his ability to keep fellow Republicans in line, the county supported a Democrat for president in 2016 for the first time since Lyndon B. Johnson led the ticket.

The much-anticipated future of Texas politics may not have arrived statewide yet, but it is hard to miss in the booming, polyglot metropolitan areas that are changing the face of the state.