First-year enrollment at U.S. law schools plunged to levels not seen since the 1970s, as students steered away from a career that has left many recent graduates loaded with debt and struggling to find work.

The American Bar Association said on Tuesday that the number of first-year law students fell 11% this year. So far, 39,675 full-time and part-time students enrolled in law school, nearly 5,000 fewer than in 2012.

That's...