Mitt Romney won Republican presidential primaries in New Jersey, New Mexico and South Dakota Tuesday, adding to a delegate total that already exceeds the number needed to win the nomination.
Presidential primaries were also held in Montana and California.
A total of 264 delegates were at stake in Tuesday's contests, and Romney has a chance to win them all. Romney has 1,266 delegates. He needs 1,144 to win the nomination.
With the primary season winding down, Romney is already in general election mode. He will take on Democrat Barack Obama in the fall.
After Tuesday, only one Republican presidential primary remains, in Utah on June 26.
Romney has recently been concentrating on raising campaign funds. His two-day swing to Texas is expected to garner $15 million for his presidential campaign.
Romney supporter Ray Washburne told the crowd at a Dallas fundraiser Tuesday that the presumptive Republican nominee would raise that much at a slew of meetings. Some $3.5 million was expected be raised from almost 500 people at the Belo Mansion in downtown Dallas.
Tickets start at $2,500 for a reception, $10,000 for a photograph with the governor, and $50,000 for dinner.
Romney has fundraisers scheduled Wednesday in San Antonio and Houston.