score:5
Assuming you are of legal age in the US and Canada, they have a site listing all the restrictions.
It's not very much, unfortunately, limiting you to around 8.5L or roughly 24 cans.
However, their alcohol specific page which also says the same thing, does mention that it may vary by province, but I wouldn't expect it to vary much.
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Alcohol is ONE of the categories that you can bring in duty free, up to the specified limit (others are things such as tobacco products).
It IS possible to pay duty if you wish to import more, but it may be easier to just buy them in Canada, depending on the location and type of beer.