Thanks everyone for your responses. Hitch pin for a tractor. That makes sense since where I detected it along the creek here in town was a (farm field-cow pasture) up until the mid 1900s. It is now overgrown and one would never know. It also boarders what was once a spur of the Pennsylvania Railroad. I know they had hitch pins for railroad carts too. So thanks again to all, especially relic nut, for your input. It is really great to be able to find out about finds you have questions about from very knowledgeable people.