The man died in a shooting around 5 p.m. Saturday on the outskirts of Clinton, in the municipality of Central Huron, Ontario Provincial Police said in a release issued Sunday afternoon.
Jamie Stanley, a spokesman for the Huron OPP, said residents should "be aware of their personal safety at all times."
Investigators also set up a command post at the scene, Stanley said in an email.
"We have numerous resources involved in trying to determine who is responsible for this shooting," he said, adding it was too early in the investigation "to discuss specific details related to the victim or other involved persons."
A police tactical team swept the area Saturday night but did not find any suspects, Stanley later told reporters at the scene, adding it wasn't clear whether one or multiple people were involved.
"At this point in time do we have a suspect? Do we have suspect descriptors, that we like to provide to the public? We do not have that," he said.
Officers remained on the scene looking for evidence and were doing forensic work but there was no threat to public safety, Stanley said, adding information from the scene has led police to believe the death was criminal in nature, but wouldn't elaborate.
Police cruisers were stationed along dirt access roads far from the scene of the shooting, a wooded wildlife area bordered by small farms and houses, as other police vehicles including black SUVs entered and exited the cordoned-off zone.
Central Huron Mayor Jim Ginn said police cordoned off a large area outside on the outskirts of town.
In the ensuing confusion, some residents and some media outlets reported that residents were ordered to stay inside with their doors locked, but both Ginn and police said that was never the case.
"They're not asking people to stay indoors at this point, but to be a little more cautious," Ginn said Sunday.
He explained that a town siren that went off Saturday night, which some residents took as a signal to remain indoors, was connected to an unrelated fire.
Yvonne McLean, who lives on a hobby farm close to the Hullett Wildlife Conservation Area, said she watched as police cruisers sped past through the night on Saturday.
She said many officers remained on watch on Sunday.
"I feel safe with the officers out there," she said.
"They were out there keeping an eye out."
Diane Proper, another resident, said she went to the cordoned off area on Sunday and saw dozens of police vehicles and a few ambulances.
According to Proper, the wildlife site is popular with hunters and horse riders, and there was bird-dog training held there over the weekend.
She added that rumours and speculation were rampant as residents tried to figure out what was going on.
"Everybody is just scouring what they can to get some confirmation... why the silence? Why the mystery surrounding this?"
"Give us something. Should we be in fear of our lives or have they got everything under control?"
Clinton, a community of 3,100, is about 76 kilometres northwest of London near Lake Huron. Ginn said shootings aren't the kind of occurrence that residents are used to.
"You hear it all the time, but you don't expect those types of things to happen in an area like this."
(The Canadian Press, BlackburnNews.com)
_ With files from Benjamin Shingler in Montreal