Ontario Provincial Police say one person is dead and two others were seriously injured in a collision that closed the 401 in both directions near Prescott.
Police say a tractor trailer and two other vehicles were involved, but wouldn't provide other details.
Around 8:30 pm, the westbound lanes of the 401 re-opened to traffic. Overnight Sunday, the eastbound lanes also re-opened.
The investigation is ongoing.
The crash happened as many commuted home from the popular Brockville Tall Ships festival. The annual event attracts tens of thousands to the area.
UPDATE: ROAD CLOSURE: #Hwy401 remains CLOSED EB at County Rd 15 and WB at Edward St #Prescott. Detour NB at Edward St to County Rd 26.^lp
— OPPCommunicationsER (@OPP_COMM_ER) September 18, 2016
Stay tuned for more information.Backed up traffic on Hwy 401 e/b east of Brockville Lone car going w/b due to multi-car crash @ctvottawa pic.twitter.com/DveJrfnyy1
— carolan w. lesaux (@cwadsworthCTV) September 18, 2016