Rabbi Shlomo Elkan hadn’t heard of Oberlin College before heading there in 2010 to establish a Chabad House, which functions as a campus center for Jewish students. “Rural Ohio wasn’t on my radar,” the 34-year-old rabbi, who grew up in Atlanta and received his rabbinical training in New Jersey, tells me. But a third of students at Oberlin are Jewish, and the Corn Belt seemed a quiet place to raise a family. Little did he know.

The rabbi and his wife, Devora, quickly drew regular attendance to services at their small home,...