Chestnuts are specially rewarding to glean from public trees. No ladder needed, they fall to the ground when ripe.
It’s important not to get confused with the non-edible type of chestnut. These so-called “horse chestnuts” are bitter, mildly toxic, and come from different trees and different shells. Once you know the differences you can be sure to get the edible, delicious kind (here one article, and another explaining how to tell them apart).