Deputies responded to the area of Lafayette Boulevard and Lorraine Avenue at about 6:30 p.m. for a report of a suspected drunken driver, police said.
The caller, a pizza delivery driver, told authorities she saw a Chevrolet Tahoe swerving on Lorraine Avenue. She told police the vehicle had gone into a ditch and stopped.
The witness also told authorities she saw a child banging on the passenger window and then getting out of the car.
The Tahoe then drove away, police said, leaving the child behind.
A deputy arrived and found a 10-year-old girl sitting in the pizza delivery driver's car. The child told the deputy that her mother had been driving and that she was scared because of the way her mom was driving.
A deputy located the mother's car on Lafayette Boulevard and police say the driver was visibly intoxicated.
Tara Dawn Biller, 30, of Fredericksburg was charged with DUI and driving on a suspended license. She was also charged with refusing a breath test and child endangerment.
The child was released to family members.