Republican presidential candidate Donald Trump speaks at a rally in Billings, Mont., on May 26, 2016. (Photo by Spencer Platt/Getty Images)

BILLINGS, Mont. — Here’s a key part of Donald Trump general-election strategy: He plans to focus on about 15 states, including some where Republican nominees don’t often campaign.

“We have to win, and I want my energy to be put into the states where it could go either way,” Trump said at a rally here on Thursday evening. “And we’re going to play heavy, as an example, in California. Now no other Republican — they wouldn’t even go to dinner in California. They wouldn’t do it.”

But that means Trump won’t be returning to Montana, which he described as “very much a Republican stronghold.” Trump said that as he drove from the airport to the rally site, he passed a number of people who cheered him on. He took that as a signal that he has this state locked down and doesn’t need to spend much more time here. The crowd seemed to take the news well and one man in the crowd shouted that he had Trump’s back.

So which states will Trump target? California. Ohio, where he plans to spend a lot of money. Michigan. New York, his home state which was once represented by Democratic front-runner Hillary Clinton in the U.S. Senate. Florida, where he owns several golf resorts and a private club where he often lives. And Virginia, which is also home to a Trump golf course.

The Associated Press, which tracks each candidate’s delegate tallies and the commitment of delegates, announced Thursday that Trump had exceeded 1,237 — the number needed to secure the Republican nominate. He is expected to be formally installed as the nominee at the party’s convention in Cleveland in July.

Trump said that his strength as a candidate is sometimes misunderstood and that his vote percentages in many states would have been even higher if he didn’t have so many Republican rivals.

“We don’t get enough credit,” Trump said at the rally. “I say ‘we’ because we’re like a group. We won today. We won — not me, we all won today.”