Mardi Gras is referred to as a movable feast, meaning it can be held on a wide range of days each winter. The landing date is determined by the calendar and can be from early February until early March.

Thanks to its proximity to New Orleans’ most ballyhooed holiday, the race that now is called the Rock ‘n’ Roll New Orleans Marathon also is a movable feast of sorts. It too changes dates to work around the Herculean effort required to stage Carnival.

That can have a minor effect on the number of participants who register for the marathon each year, but it certainly hasn’t diminished the race’s impact.

This year, the Rock ‘n’ Roll New Orleans Marathon will be held Sunday, Jan. 25, beginning at the corner of Camp and Poydras streets in the CBD and finishing at Roosevelt Mall in City Park. More than 13,000 competitors — hailing from each of the 50 states and from more than 25 other countries — are expected to take part.

The race, under its current handle, is only six years old. But many locals remember the race when it was called the Mardi Gras Marathon and held right around the Carnival feast each year.

The difference, said race director and New Orleans resident Malain McCormick, is that the Rock ‘n’ Roll group promotes the marathon “nationwide and worldwide.” Throw in a half marathon, a 10-kilometer race and a relay competition all staged at the same time on the same course, and Rock ‘n’ Roll New Orleans is a success, she said.

“We have doubled or tripled in some cases what the Mardi Gras Marathon and half marathon were doing, I think,” she said. “Seventy percent of the people who are registered are from out of the greater New Orleans area. It’s a really exciting race for the people that come in.”

McCormick said the half-marathon distance is easily the most popular of those her race offers. An estimated 8,500 are expected to take part in that 13.1-mile run, while about 3,000 will take part in the full 26.2-mile marathon. Another 1,000 are expected in the 10K, and 700 will be part of relays in those races.

“The half marathon has become the most popular distance because it’s easier to train for in the winter,” she said. “But the big thing is that, whichever race you run ... the course is super flat and super fast. That in itself draws people. It’s also a good qualifier for (the Boston Marathon).”

So where exactly does Rock ‘n’ Roll New Orleans stack up against the other dozen-plus marathons that carry the same brand name?

“I’m partial because I’m a native New Orleanian and I think it’s the best,” McCormick said. “But all of our competitors tell us it’s one of the best races they go to and certainly in the top 10. We put on a great race, but it’s also a great party.”

Registration is ongoing online at runrocknroll.com/new-orleans. There will be food, drink, live entertainment and more at the start and finish. A portion of proceeds will benefit the Feed the Children organization.

A health and fitness expo will be held Friday, Jan. 23 from noon to 6 p.m. at the Morial Convention Center, Hall J. It also will be held from 9 a.m. until 5 p.m. on Saturday, Jan. 24. The expo is free and open to the public.

On Sunday, Jan. 25, the 10K race will begin at 7 a.m. with the marathon and half marathon beginning at 7:30. KONGOS and Trombone Shorty will headline a post-race concert at the finish line in Roosevelt Square.