One of the resources mentioned by Dr. William Roulston, Research Director of the Ulster Historical Foundation, during two of three of his talks I caught at the BIFHSGO conference just ended, was the Belfast Newsletter. It started publishing in 1773 and is still a going concern.
According to information from the Belfast newsletter index website at www.ucs.louisiana.edu/bnl/
"it was published thrice-weekly during the 18th century, in issues of four pages each. During its time, the Newsletter was seldom equalled in the breadth and quality of its coverage of local and international events.While the results you will get are an index, an electronic version of the newsletter may be available at a university library local to you. The University of Ottawa Library has a subscription.
Every significant word and date in the 20,000 surviving pages of the newspaper was indexed, but not all of the newspapers are still available. In fact, only about one-quarter of the newspapers for the years from 1737 to 1750 have survived, although the run of newspapers is nearly complete from 1750 through 1800 (Click here for a list of surviving newspapers). The final database of information contains nearly 300,000 items of news and advertisements."