Religious Jewish communities have migrated across the New York region for decades, generally either settling in suburban areas or creating new enclaves in empty expanses. In the 1950s, a group followed a charismatic rabbi to Lakewood, N.J., and today Orthodox Jews make up a major part of the community there. In the late 1970s, Hasidic Jews migrated to Orange County from Williamsburg, Brooklyn, setting up the insular town of Kiryas Joel. And on Long Island, secular Jews have recently sparred with their more religious counterparts in the Five Towns.

Image An afternoon prayer service at the yeshiva in Waterbury, where more than 100 families shape a community. Credit... Christopher Capozziello for The New York Times

But it is practically unheard of for Orthodox Jews to flock to dilapidated midsize cities like Waterbury, a place few people have lately seemed interested in moving to, and where there is virtually no other Jewish presence.

A former industrial hub about a two-hour drive from either Boston or Manhattan, Waterbury has grappled for years with an eroding business base and declining property values. Once-resplendent homes have long been vacant and tarnished by graffiti. Though an influx of immigrants from Latin America and development projects have helped the economy in recent years, downtown still has scars of decades of decay.

Enter Rabbi Kaufman and his followers. With the help of real estate developers in 2001, the city’s political leadership courted the Jewish leaders, offering a $60,000 lease on a former campus of the University of Connecticut in exchange for a promise to bring in 100 families by this summer.

That goal was reached a year ahead of schedule. The kindergarten-through-eighth-grade school expanded from one to two buildings on the university campus, and is expected to soon fill all five buildings there. The high school will award its first batch of diplomas next summer. And the yeshiva, the adult religious school that is the heart of Jewish life here, is moving its dormitories into a 10-story apartment building in the center of town later this year.

The families who move here are drawn in large part by economics — Yisroel Weinreb, 23, who originally came from Brooklyn to study at the yeshiva as a teenager, bought a six-bedroom house for $160,000 in 2005. Now he is remodeling the basement.