Phoenix Feeley had refused to pay the fine in a protest against the city of Spring Lake's anti-nudity ordinance, NJ.com reported.
Cynthia Scott, a spokeswoman for the Monmouth County Sheriff's Department, said Feeley had been released "on time allotted."
After the release, GoTopless.org posted a message on its Facebook page it attributed to Feeley.
"Out of jail," the message said in part. "After 48 hours of no food or drinkable water and telling the judge I'd never survive 16 days like that, they began to give me water and consequently I live to tell the tale."
Feeley surrendered to corrections officials Aug. 5 after the New Jersey Supreme Court refused to hear her case last year.
She had refused to pay $816 in fines for being arrested twice in the same day in 2008 while sunbathing in Spring Lake.
Feeley claimed that being topless was not the same as being nude. She told the judge at her sentencing "I refuse to pay a fine for an act that is legal for a man but is illegal for a woman."
Toddler uninjured after being knocked over by Obama family dog
Martin Bashir resigns from MSNBC over Sarah Palin comments