Sunrise Highway in North Patchogue reopened just before 3 p.m. Friday after being closed for more than six hours.
The roadway was closed after a 911 call at 8:22 a.m., Suffolk County police said.
Police declined to characterize the nature of the closure, only saying the road was closed because of "police activity at the overpass." Emergency Service Unit officers responded to the scene.
The closure caused significant traffic delays in the area.