Thanks for your question on the difference between horse chestnuts and edible chestnuts. It can be confusing since both trees have the word chestnut in their common name. But the differences stop there.
Horse chestnut is a different genus and species (Aesculus hippocastanum) and the fruit are inedible and considered poisonous. More info and photos here: https://landscapeplants.oregonstate.edu/plants/aesculus-hippocastanum
The edible chestnut that you may purchase in groceries stores is in a different genus (Castanea) and there are several species. There were some major issues with a plant disease that wiped out many chestnut (Castanea sp.) trees but they are slowly making a comeback. Here are some photos of a Castanea tree. https://landscapeplants.oregonstate.edu/plants/castanea-sativa
If you have any doubt, please get the tree properly identified. You can drop samples off at the OSU Extension Linn County office. It's best to bring in leaves and nuts in shells. Driving directions and open hours can be found here: https://extension.oregonstate.edu/linn
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