Jeh Johnson, the Homeland Security secretary, said last month that a committee would conduct an internal review of the privately run family detention centers by November. Immigration and Customs Enforcement officials said that the Berks center, run by the county, would be evaluated in a separate review.

Image The detention center in Berks County, Pa., about 70 miles northwest of Philadelphia, where the women and children are being held. Credit... Mark Makela for The New York Times

When Mr. Johnson said last month that the average length of stay at a family detention center was 20 days, that upset the women in Berks and prompted their hunger strike.

“I have been here for 320 days,” Amparo Osorio, 26, who came from Honduras and has a 2-year-old son, said on Tuesday. Like all the women detained at Berks who spoke in telephone interviews conducted in Spanish, she asked not to be identified by her complete name, for fear of retaliation by staff members.

“What we want is for our voices to be heard,” Ms. Osorio said.

Senator Bob Casey, a Democrat from Pennsylvania, sent a letter on Aug. 24 to Mr. Johnson about the prolonged detentions and the conditions at Berks.

“The families detained there have in many cases escaped unspeakable horrors in their countries of origin and are seeking asylum and a better life, ” Mr. Casey wrote. “We can do better than the treatment they are receiving.”

Bridget Cambria, one of three local lawyers who represents the detainees, said there are limited services available to the families at Berks. Children, who range in age from 2 to 16, are divided into two classrooms, but are not allowed to attend an outside school. (The government said it provides five full-time teachers.) The families have access to outdoor recreation, but are prohibited from going outside a wooden fence. They can use the internet, but social media is not allowed. The detainees must clean the center themselves — for which they get paid $1 a day.

The mothers say the monotony is hardest on their children. “We wake up and we see the same walls, the same ceiling, and we think to ourselves, ‘When will this end?’” said Estefani, 16, the oldest child at Berks. She and her sister and their mother, Maria Leiva, who came from El Salvador, had been in detention for 373 days as of Friday.