The reality show star, who checked into jail in this Los Angeles suburb at 3:15 p.m., was released at 4:37 p.m. "based on her sentence and federal guidelines," Los Angeles County Sheriff's Deputy Maribel Rizo said without elaborating.
When asked whether Richie spent her brief sentence in a jail cell, Rizo replied: "No further comment."
TheInsiderOnline.com was the first to report the story.
A call to Richie's attorney, Shawn Chapman Holley, was not immediately returned Thursday. An e-mail message to publicist Nicole Perna was not immediately answered.
The reality show star entered a county jail for women in this Los Angeles suburb shortly after 3 p.m., Los Angeles County Sheriff's Deputy Johnie Jones said.
It's the same facility that housed her "The Simple Life'' co-star Paris Hilton for nearly three weeks after she was convicted of driving on a suspended license while on probation for an alcohol-related reckless driving case.
It was reported earlier this month that Richie wanted to do her time in the Los Angeles County jail.
Richie's lawyer contacted the county sheriff's department earlier this week and indicated the reality TV star wanted to serve her four-day sentence in county lockup rather than a city jail, sheriff's spokesman Steve Whitmore said Thursday.
Whitmore said he had no additional details at the time, including when Richie might surrender to begin the sentence that she had to complete by Sept. 28.
A call to Richie's attorney, Shawn Chapman Holley, was not immediately returned.
The county has a special women's-only facility in Lynwood. It's the same place where Richie's friend Paris Hilton recently completed a 23-day stay for violating probation in an alcohol-related reckless driving case.
Richie said in an interview last month that becoming pregnant made her realize that she needed to change her life and take responsibility.
"I owe the baby my life," she told Diane Sawyer on an interview aired on ABC's "Good Morning America." "I owe this baby everything and I have a responsibility now. I'm now responsible for someone else. I need to set the right example."
With her rocker boyfriend Joel Madden at her side, Richie explained what happened on Dec. 12, the night she was arrested for driving under the influence.
She said she was driving on the freeway near Glendale, Calif., a neighborhood unfamiliar to the 25-year-old reality star.
"When I was getting off the off ramp, instead of making a left to get on the street, I went back on the off ramp," she said. "And I was in such shock that I just stopped the car. Then, within two seconds, police were there and we got off the freeway."
Richie admitted that she had been smoking marijuana and had taken the prescription painkiller Vicodin earlier in the day. She said she thought she was OK to drive.