Saturday morning, roughly 60 tons of freight will pass over the Old Mississippi River Bridge and back.

A couple of hours later, a train will cross, too.

The 27^th annual Over the River Run, a 5-mile run and race walk, is scheduled to begin at 8 a.m. at the foot of the 85-year-old span over the Mississippi River. More than 600 people have already registered, race director Stacey Massey said, and as many as 900 could sign up by the time the race begins.

Massey said the setting and novelty of the race, as well as its various events that cater to all ages and skill levels, make it one of Vicksburg’s favorite annual events. In addition to the run and race walk, there will be a 1-mile children’s fun run.

“That’s a beautiful setting. People in Vicksburg and people visiting Vicksburg already go to the overlooks and the bridges to take pictures, and this is another thing that showcases that,” Massey said. She is also director of the Southern Cultural Heritage Foundation, which organizes the race. “To go to Mississippi and Louisiana, and back to Mississippi, this is probably the only place you can do it. And, of course, you’re taking care of your body. You can pick the 5-miler or the walk, or the fun run. There’s something at every level. Just pick what level is comfortable for you.”

Although it’s been a Vicksburg staple for more than a quarter of a century, it’s only been in recent years that the Over the River Run has exploded in popularity. Until 2009, participation numbers hovered between 350 and 400 people annually.

In 2010 the Southern Cultural Heritage Foundation took on organizing duties and breathed new life into the event. Participation grew each year from 2010-2013, peaking at 829 people in 2013. That was the first time the Over the River Run surpassed the well-established Run Thru History as Vicksburg’s biggest road race.

A total of 875 people registered for the 2014 race, but only 749 completed it. The two numbers are often different as some registered runners are not officially scored or don’t show up for various reasons.

“It’s just catching on,” Massey said. “People are realizing the beauty of Vicksburg and the bridge. We have great members of the Cultural Center and we have a great group of volunteers. The Cultural Center brought some new life to it.”

The race is the biggest annual fundraiser for the Southern Cultural Heritage Foundation. Massey said last year’s Over the River Run raised more than $15,000 for its general fund, which typically covers the cost of building maintenance and projects.

The SCHF is currently trying to fund a major roofing project, Massey said, and the proceeds from the race will help pay for it.

“Three of our five building need roof work. We applied for a grant, but even if we get it we need a match of $36,000. This run could help with that, or it could go to any building rehabilitation or maintenance needs we might have,” Massey said.

Nearly two dozen sponsors help cover organizational and advertising costs, which lets the SCHF keep most of the money from entry fees.

“That’s why we can be successful with our fundraiser, is because we have people helping out,” Massey said.

Early registration for the Over the River Run is open until Friday at 7 p.m., at the Southern Cultural Heritage Center, 1302 Adams St. The registration fee is $30 for adults and $15 for children 10 and under. There’s also a $55 family rate for up to five people, and a $75 corporate rate.

Raceday registration will be available Saturday from 6:30 to 7:30 a.m. in the parking lot of the Mississippi Welcome Center on Washington Street.

Those who have pre-registered can pick up their race packets from 4 to 7 p.m. Friday at the Southern Cultural Heritage Center, or in the Welcome Center parking lot during the raceday registration period.

After the race, an awards ceremony and party will be held in the Ameristar Delta Point parking lot on Washington Street. Refreshments will be served, music will play and massages will be available and there will even be a couple of inflatable castles for children to play in.

“After the race, we get to have fun,” Massey said with a laugh.