After a forceful win in New York, Donald Trump has a narrow but real path to 1,237 delegates, the number required to avoid a contested convention.

He needs about 390 more delegates to become the Republican presidential nominee. Here’s one way he could get them.

Pick Up 185 in the Industrial East

Mr. Trump is a big favorite in the remaining states of the industrial East, from West Virginia to Rhode Island, so he could garner a commanding haul here. Mr. Trump will probably fall a bit short in places — perhaps yield a district or two in Maryland, or lose ground because of the complicated rules in West Virginia. But he might still come away with around 185 of these delegates, covering nearly half of the remaining distance to 1,237.

Gather 34 in the West and Midwest

Mr. Trump is not particularly popular out in the Mountain West and Plains. Ted Cruz is favored in winner-take-all contests in South Dakota, Montana and Nebraska. But Mr. Trump might still emerge with delegates from Washington, Oregon and New Mexico, which award their delegates proportionally. He might win 34 of these delegates, even if he loses.