The first ever Silo District Marathon on Sunday is expected to be the largest race ever held inside the city of Waco.

Waco sweethearts Chip and Joanna Gaines are doing it again, hosting an event expected to draw up to 18,000 people.

“We are well aware that we are going to get a large contingent of people into the Waco area,” said Sgt. Patrick Swanton, Waco Police Department.

In fact, about 6,000 people will run in the 5K, half-marathon and marathon courses, including Chip himself. Another 10,000 are expected to support the runners.

“It’s going to be crazy,” said Tammy Cory, visiting Waco from Florida.

Cory says the marathon already made her change her plans.

“It was crazy, so we wanted to stay the weekend but the hotels were so busy so we had to change our dates to weekdays and then we found out the marathon was Sunday,” said Cory.

Thousands of others might have to change their plans to adjust to the many street closures.

“Obviously that’s to protect the participants that are going to be involved in this and I think if we all just keep an extra eye out and a little bit of patience goes a long way in these kind of events,” said Sgt. Swanton.

Law enforcement is ready for the huge turnout.

“You can expect to see a pretty good contingency of officers, not only on duty, but the Magnolia group is also hiring off-duty officers to come in and assist,” said Sgt. Swanton.

There will be free event parking at 3125 Dutton Avenue and free shuttle service provided by Waco Transit.

“And everybody can end up having a safe, happy event and we can showcase Waco,” said Sgt. Swanton.

100% of the profits from the race will go toward the much-needed research on rare cancers.

Traffic will be affected between 7am to 2pm Sunday, May 6th.

Click HERE to see a full list of closures.