Amwell Township was established by a royal patent from Queen Anne in 1708. Its territory comprised and included present day Delaware Township, Raritan Township, Readington Township, East Amwell Township and West Amwell Township and portions of Clinton, Lebanon and Tewksbury Townships. Both East Amwell Township and West Amwell Township were formed on April 6, 1846, when Amwell Township was split in two. Territory was gain in 1854 from Delaware Township, Raritan Township and West Amwell Township, and again from those same three townships in 1897. The township was named for Amwell Township, which in turn was named for Amwell, Hertfordshire in England.