ELDORADO, Texas — More than 400 children, mostly girls in pioneer dresses, were swept into state custody from a polygamist sect in what authorities described yesterday as the largest child-welfare operation in Texas history.

The days-long raid on the sprawling compound built by now-jailed polygamist leader Warren Jeffs was sparked by a 16-year-old girl’s call to authorities that she was being abused and that girls as young as 14 and 15 were being forced into marriages with much older men. Dressed in home-sewn, ankle-length dresses with their hair pinned up in braids, some 133 women left the Yearning for Zion Ranch of their own volition along with the children.

State troopers were holding an unknown number of men in the compound until investigators finished executing a house-to-house search of the 1,700-acre property, which has a medical facility, a cheese-making plant, a cement plant, a school, numerous large housing units, and an 80-foot white limestone temple that rises discordantly out of the scrub.

“In my opinion, this is the largest endeavor we’ve ever been involved in in the state of Texas,” said Children’s Protective Services spokesman Marleigh Meisner, who said she was also involved in the 1993 siege of the Branch Davidian compound in Waco.

The members of the Fundamentalist Church of Jesus Christ of Latter-Day Saints spent their days raising numerous children, tilling small gardens, and doing chores. But at least one former resident says life was not some idyllic replica of 19th-century life.

“Once you go into the compound, you don’t ever leave it,” one of the wives of the alleged leader of the Eldorado complex, Carolyn Jessop, said. Ms. Jessop left with her eight children before the sect moved to Texas. She said the community emphasized self-sufficiency because they believed the apocalypse was near.

The women were not allowed to wear red — the color Jeffs said belonged to Jesus — and were not allowed to cut their hair. They were also kept isolated from the outside world.

Still uncertain is the location of the girl whose call initiated the raid. She allegedly had a child at 15, and authorities were looking for documents, photos, even a family Bible with lists of marriages and children to demonstrate the girl was married to Dale Barlow, 50.