Seeking a slice of that bounty, communities like Farmville, Va., and Pahrump, Nev., are signing up with developers of new detention centers. Jails from New England to New Mexico have already made the crackdown pay off  for the private companies that dominate the industry, for some investors and, at least in theory, for places like Central Falls, a city so strapped that the state pays for its schools.

Here, a specially created municipal corporation built the jail in the early 1990s to hold federal inmates, and last year more than doubled its size. As the City Council president, William Benson Jr., put it, “The more inmates they have, the more money we get.”

Yet in a community whose 1.3 square miles are said to be too small for secrets  “If you sneeze on Washington Street, someone on Pine Street says, ‘Gesundheit,’ ” Mr. Benson said  city officials, overwhelmingly non-Latino, seemed uninformed about who those inmates were. “Nobody knows exactly who’s down there,” he said. “I hear some are Arab terrorists.”

The mystery is in some ways understandable. Though immigration detainees made up one-third of the daily population and a majority of the 4,200 men and women who moved through Wyatt’s 722 beds in a year, most were from other states, and those from Rhode Island did not remain long: Immigration and Customs Enforcement typically transferred them within a week.

Some were legal immigrants who had served time for serious crimes. But increasingly they were the kind of people who in the past would not have been arrested  people without papers, similar to some of the people who play, cheer and live in Wyatt’s shadow. Sometimes the same people.

Anthony Ventetuolo Jr., one of Wyatt’s developers and now the jail’s chief executive, said that who the inmates were made no difference to the jail, which was run like a business, under strict standards. “I’m not interested in getting involved in the politics of immigration,” he said. “All we do is detain people that our clients tell us to detain.”

Swallowed by the System

Over 10 years, Maynor Canté, 26, hardly glanced at the jail he passed as he hurried between home, two jobs and St. Matthew’s Church, where he led a prayer group.