Fahy's daily diary entries, written for the most part on loose sheets, concern his farm Deerpark at Quin, Co. Clare and farm work, notably the birth, care and sale of livestock, hay making, hiring labourers, paying their wages and their attendance at work, bee keeping, harvesting crops, acquiring farm machinery, selling produce and ongoing maintenance work on the farm, including building walls and drainage schemes. While the diary entries are principally a log of farm activity, he also records other aspects of his routine in detail, notably his work at the County Council Offices in Ennis where he was a clerk and later accountant, visitors to his home, local funerals and weddings, family illnesses, his attendance at hurling matches, fairs, point to points and coursing meets, his purchase of furniture and his trips to Lisdoonvarna, Lahinch, Kilkee and Doolin. The collection contains diary entries for the years 1902, 1905 and 1916 to 1953; some text is illegible.