A John Shea was granted lands in a number of county Galway baronies in March 1678/9. Gartside Shea of Shinnanagh, parish of Omey, barony of Ballynahinch, was active in seeking relief for those suffering from the effects of famine in the Ballinakill district in the 1840s. The immediate lessor of Shinnanagh at the time of Griffith's Valuation was Edmund O'Flaherty and G. Shea may have purchased the townland, which he already held on lease, from the sale of the O'Flaherty estate in 1862. Shinnanagh is a townland of 639 acres and one source records Gartside Shea as proprietor of that amount of acres. Maria Shea of Ballinasloe is recorded as the owner of over 639 acres in county Galway in the 1870s.