A little research will show in the states at least they belong to whoever owns or has rights to the land.
Of course the US has to dabble on everything so if it's public land then there are rules.
A little more digging and you find this.
"Canadian law on the matter is clear and simple: Any meteorite found in Canada belongs to the owner of the property it was found on. There is no distinction between privately-owned or publicly-owned land (as far as this author can determine) in this rule, so apparently anything that falls on federal or provincial government land is the property of the government."