*Editor's note: This story has been updated to reflect the governor's proclamation.
Early voting will run Sept. 10-14.
The runoff pits Republican Pete Flores against Democrat Pete Gallego. They were the top two finishers in the first round of the special election, which was held July 31 and included six other candidates.
The runoff date was first revealed Monday by lawyers appearing in Travis County court for a case challenging the eligibility of Gallego, the former congressman and longtime state lawmaker from West Texas. Abbott issued a proclamation officially setting the date of the runoff shortly after the hearing was over.
The Republican Party of Texas is suing to remove Gallego from the ballot, alleging he does not live in the district as required by state law. At the hearing, a lawyer for the state party unsuccessfully sought to block the Texas secretary of state from certifying the candidates for the runoff.
Uresti resigned earlier this year after being found guilty of 11 felonies, including securities fraud and money laundering, prompting a special election to replace him.