WESTPORT — The rolling thunder from thousands of motorcyclists will be heard Sunday as the 23rd CT United Ride — a tribute to victims of the Sept. 11, 2001, terror attacks — gets underway at Sherwood Island State Park.

The event, said to be the state’s largest 9/11 commemoration, is set to hit the road about 11:30 a.m. Sunday, Sept. 8, after same-day registration takes place from 8:30 to 10:30 a.m. at the park. (Advance signups take place from 11 a.m. to 5:30 p.m. Saturday, Sept. 7, at Captain’s Cove Marina on Bostwick Avenue in Bridgeport.)

CT United Ride’s 60-mile route, in addition to Westport, passes through nine other Fairfield County communities before ending at Seaside Park in Bridgeport. It is sponsored by the Uniformed Professional Fire Fighters of Connecticut.

In Westport, after the motorcycle procession leaves Sherwood Island it travels south on Interstate 95 to Exit 17 at Saugatuck Avenue, and then heads north through town via Route 33 before entering Wilton.

Intersections along the Westport route will be closed to through traffic while the entourage passes through town.

In addition to paying tribute to victims of the 9/11 attacks, organizers say this year’s ride also honors the service of four state first-responders killed in the line of duty over the last two years — Bristol police Lt. Dustin DeMonte and Sgt. Alex Hamzy, North Haven Firefighter Matthias Wirtz and State Police Trooper Aaron Pelletier.