The group said the snake is now believed to be a pet that either escaped from its home or was abandoned by its previous owner.
Experts said corn snakes are not native to Canada and the animal would be unlikely to survive a winter in the area.
"The reason we do not want this animal in the wild is because there is always a chance that pets of any kind can carry an illness that could be transmitted to our native wildlife. Even dogs and cats can potentially carry pathogens dangerous to wildlife," Scott Gillingwater, a conservation authority biologist, told the Woodstock Sentinel Review.
The conservation authority is asking members of the public to keep an eye out for the snake in the conservation area and the surrounding region.