The Northampton Mercury was established in Northampton in 1720 by printers William Dicey and Robert Raikes who also published the Gloucester Journal. In 1725 Raikes and Dicey dissolved their partnership. Raikes continued as sole proprietor of the Gloucester Journal while Dicey retained the Northampton Mercury. Early issues of the paper included woodcut illustrations and mostly foreign news with little or no local news.

Advocating liberal principles, the Mercury was described by Mitchell in 1846 as a paper for the common good, not bound by any particular interest, party or sect.

The paper remained in the Dicey family until 1885 when the trustees of Mrs Ann Mary Dicey sold it to Samuel Smith Campion. Campion, who also took over the role of editor, was a founder member of the Institute of Journalists.