Stinging Nettle is part of Castlewood State Park. This is outside of St. Louis. This trail is right along the Meramec River and tends to retain water making it very muddy in puddles. This is a fun trail and I would rate it at a beginning level. If you get more adventurous, go over to the main parking lot at Castlewood. Try the Love trail - this is a little bit more challenging than Stinging Nettle.

Oh, one more thing, definitely apply some lube onto your chain.