According to Lewis’s Topographical Dictionary (1837),
The principal trade is in wool, for which this is the greatest mart in the county, its central situation and facility of communication with the Shannon and with Dublin having rendered it the commercial centre of a wide extent of country. The City of Dublin Steam Company commenced operations here in 1830: a steamer plies twice a week between this town and Shannon Harbour, where it meets the Limerick steamer and Grand Canal boat for Dublin.
It is interesting that the steamer went west and south (37 miles, 21 locks to the Shannon, then river, lake and river to Shannon Harbour), rather than directly eastward (52 miles, 25 locks) to Dublin, but its route would have enabled it to serve Longford, Tarmonbarry, Lanesborough and Athlone. Lewis, however, does not mention steamer services at any of those places other than Athlone.
More research required ….
Irish waterways history 