Allin's Cove is a tidal estuary just south of Bullocks Cove in West Barrington. Most of the cove is fringed in salt marsh, and it is fed through a 6-foot wide channel that runs approximately 75 feet into the cove from the Providence River. Information on the history of this area can be found here.
You're looking for a pill bottle. There is a log sheet inside, but no pen so you will want to bring your own writing utensil. Please be respectful of other people's property and rehide the cache as you found it. The hint is designed to help you as there are a lot of potential hiding spots, so use it to ensure a (hopefully) quick find!