Can I purchase or consume marijuana in Ontario?
As of October 17, 2018, the purchase, use and possession of recreational cannabis has been legalized across Canada with regulations varying by province. As a result, the province of Ontario has created rules about how, where and who can buy, possess and consume cannabis in the province. These rules are similar to those in place for alcohol and tobacco, with some differences.
You have to be 19 or older to buy, use or possess recreational cannabis, and you will only be able to use it in a private residence. Just as it is illegal to drive alcohol impaired, it is illegal to drive drug-impaired.
Until April 2019, the only way to legally purchase cannabis in the province of Ontario is from the Ontario Cannabis Store website. All products are delivered by Canada Post and an adult 19 years of age or older must be present and provide legal photo identification in order to sign for the package.
Regardless of new regulations, travellers entering and exiting Canada are still subject to inspections for prohibited goods, including cannabis, which is still illegal for consumption, possession and purchase at the federal level in the United States, as well as in most states.
See further details here on Cannabis legalization in Ontario.