Benson said he will surrender to authorities on Oct. 17, which is the Monday of Cincinnati's bye week.
"This was a difficult decision for Mr. Benson," said Sam Bassett, the running back's attorney. "His priority right now is to get back to work and put these legal matters behind him."
Benson's jail time could be significantly shorter than the sentence. He could be given credit for any time served when he was arrested and state law requires inmates be given two days credit for every day they are rewarded for good behavior. Jail overcrowding also could shorten his stay.
But for now, the Bengals must make plans to be without their leading rusher. They declined comment Monday.
Benson was arrested in 2010 for allegedly punching a bar employee in Austin, an incident that earned him a meeting with NFL commissioner Roger Goodell last year but resulted in no punishment. He pleaded no contest to a charge of assault with injury in that case.
He also was arrested last month for allegedly punching a former roommate in downtown Austin. He pleaded no contest to a charge of assault with bodily injury with family violence, and that will be dismissed if he performs 30 hours of community service and pays an undisclosed amount of restitution to the victim.
"We're pleased that Mr. Benson took responsibility for his actions today and we think this was a just result given the facts of the case," said Corby Holcomb, assistant trial director with the Travis County Attorney's Office.
The 28-year-old Benson was Chicago's first-round pick out of the University of Texas in 2005. He had two alcohol-related arrests with the Bears, who let him go in 2008.
He signed as a free agent with the Bengals and led them in rushing each of the last three years -- 747 yards in 2008, 1,251 yards in 2009 and 1,111 yards in 2010.
He was disappointed last season when the Bengals went away from their run-based offense that won them the AFC North title in 2009, then finished 4-12. After the Bengals changed offensive coordinators, Benson lobbied to stay in Cincinnati and signed a one-year deal. He provides a run-first option in coordinator Jay Gruden's new offense, which is being led by rookie quarterback Andy Dalton.
Benson also must pay a $4,000 fine within 30 days.