I have 1/2 lb. of shelled hickory nuts in my refrigerator from my favorite local farmer. Hickory trees and their nuts grow in Pennsylvania where I live so it is not that difficult for me to get some, although I have not used them in the past.
I do have childhood memories of hickory nut cake made by my grandmother for the winter holidays, but I have not tried to recreate that myself, (or at least not yet.)
Hickory trees are native to much of the Eastern United States. The nuts ripen in the fall and be gathered in the wild as well as cultivated trees. These nuts are also a favorite of squirrels so beware that they are in competition with you for these tasty nuts.
American Indians used the shagbark hickory (one variety of the trees) ground into meal for soups and stews.
How To Open Hickory Nuts
These nuts are not the easiest to open. Mother Earth News had instructions in their fall issue in 1980 and gave the following steps:
 Lay the nugget on its side and raise your hammer several inches above it.  Aim for that optimum impact spot.  Whack the nut sharply… and  it'll break cleanly into several pieces, from which you can extract the meats.
Prior to these steps the nuts should be properly cleaned and dried (in the sun works). Then these nuts can be eaten raw, or roasted. For range-top toasting, use a dry, unoiled pan—or cookie sheet—set over medium heat.
Spread the nutmeats evenly across the pan and stir them often, until they turn light brown. Then quickly move the seeds to a cool surface, so they won't continue to brown. For oven roasting, put in a large pan and roast at 179-200 degrees until they are a golden brown.
Nutritional Value of Hickory Nuts
These are high in unsaturated fats 18.2 g/SVG and are also high in protein 3.6 g/SVG.
Hickory nuts are very high in thiamine, Vit. B1. which is important to the function of your muscles, heart and central nervous system A 1-oz. serving of hickory nuts contains 12 percent of the magnesium your body requires daily.
Magnesium keeps your muscles, kidneys, and heart functioning correctly, and this mineral plays a critical role in activating enzymes and regulating calcium levels. 10% of the RDA for phosphorus.
Uses of Hickory Nuts
These nuts are good raw but can also be used in any recipe that would call for pecans or walnuts.