L.A. County Sheriff's Spokesman Steve Whitmore said Lohan is likely to be released on Aug. 1 or Aug. 2.
Lohan surrendered in court today in Beverly Hills and was booked into a Lynwood jail to start her jail sentence for violating the terms of her probation.
"People that have this kind of notoriety or with maybe a law-enforcement of a crime, they are kept away from the general population. We call that a 'keep-away,'" said Whitmore.
Attorney Shawn Chapman Holley was by Lohan's side as the actress turned herself in to the judge. Holley had resigned as Lohan's attorney earlier but never filed a formal motion with the court.
Famed celebrity lawyer Robert Shapiro, who Lohan hired last week, is not representing her anymore. L.A. Superior Court Judge Marsha Revel told the court today that Shapiro told her he would not take Lohan's case.
Lohan arrived in court 10 minutes late, but Revel did not comment on her tardiness. Revel ordered Lohan to report to probation officials and check into a rehabilitation facility within 24 hours of her release from jail. Revel also ordered officials not to allow Lohan to serve any of her sentence on house arrest or work release.
Revel ruled July 6 that Lohan violated her probation by missing multiple classes at a court-ordered alcohol-education program.
After the brief hearing, Lohan was handcuffed and led away to an unmarked sheriff's car transporting her to lockup.
Lohan was accompanied to court by her mother, Dina, and younger sister Ali. Her estranged father, Michael Lohan, yelled, "We love you Lindsay!" as his daughter was led away.
"He does not believe that she should be incarcerated. He's devastated that she's going to jail," said Lisa Bloom, Michael Lohan's attorney outside the Beverly Hills Courthouse.
Shortly after Lohan arrived at the jail around 10 a.m., Whitmore gave a brief update to the media.
"Ms. Lindsay Lohan was booked into our facility to begin her sentence. She has been extremely cooperative and everything is going smoothly," said Whitmore.
Outside the Beverly Hills courtroom, Lohan's attorney told reporters that Lindsay is scared but has stepped up to the plate.
"Lindsay is complying with Judge Revel's orders. She's completed the alcohol program. She's gone into custody. She's asked for your prayers and support and she's stepped up and she's accepted responsibility," said Holley.
L.A. County Deputy District Attorney Danette Meyers told the media that she believes Revel's sentence was "appropriate." The district attorney's office said the lesson to be learned by the public is simply not to drink and drive.
"I really think that Judge Revel has decided that enough is enough and it's time for action, and she just needs some shock therapy and she's going into custody - bye bye," said ABC News Legal Analyst Dana Cole.
Security was tight at Lynwood's Century Regional Detention Facility, mainly because the L.A. County Sheriff's Dept. were concerned that an employee might snap a mobile-phone picture of Lohan and try to sell it for money.
Lohan has been to jail before, but only for 84 minutes. This stint will be much longer.
She will be isolated from the general population at the jail and will not be mixed in with the other 2,100 inmates in Lynwood. She will be in a 12-foot by 12-foot modular cell by herself. The Lynwood jail has hosted several female celebrities, including Paris Hilton, Nicole Richie, Michelle Rodriguez, Khloe Kardashian and very briefly, Lohan.
AP contributed to this report.