ASTORIA — Once a year in October, the Astoria Bridge closes to traffic while thousands of runners take in panoramic views over the Columbia River during the Great Columbia Crossing 10K.

This year, 3,500 will participate in the sold-out race on Sunday morning.

They’ll run a 6.2-mile course starting from the Washington state side of the river at Dismal Nitch, boarding shuttles by 7 a.m. ahead of an 8:45 a.m. start time.

Shuttles will run from both Astoria and Chinook, Washington, including an ADA-accessible route from Basin Street in Uniontown.

The bridge will be closed to traffic between 8:30 and 11 a.m. Sunday, giving runners two hours to cover the 5.2-mile bridge section of the race. A sweeper bus will come through at 10:45 a.m. to pick up anyone still on the bridge. Return trips to parking areas will operate until 11:30 a.m.

The Great Columbia Crossing is organized by the Astoria-Warrenton Area Chamber of Commerce. The chamber offers $5 in “Clam Bucks” to race participants which can be spent at participating local businesses.

A virtual 10K option is also offered for those looking to participate from a distance. For full details, visit www.oldoregon.com.