N.H. Rev. Stat. Ann. § 22:8

The county of Cheshire is bounded thus: Beginning at the southeast corner of Rindge; thence westerly by the state line to the west bank of Connecticut river; thence up the same bank to the northwest corner of Walpole; thence by the northerly lines of Walpole, Alstead, Marlow and Stoddard to the west line of the county of Hillsborough; thence southerly by said west line of the county of Hillsborough to the bound first mentioned.