In pre famine times Kilmihil, was a densely populated area. Indeed the present village was far from being the largest centre of the population. In 1837 there was 3794 people in the parish with only 79 in the hamlet. with this number of people on the land (8000 acres) the country side must have been dotted with cabins. Many of these ruined structures are still to be seen.

Kilmihil has changed considerably since Samuel Lewis described it in 1837 as a small hamlet containing 79 people. The village now has a population of over 300. The parish of Kilmihil became a separate Roman Catholic division, separating from the parish of Kilmacduane, in 1848. About 120 children were educated in two private schools in 1837. One hundred and fifty years later over 200 pupils are educated in four National Schools.

The description of Kilmihil given in Lewis’ Topographical Dictionary of Ireland in 1837 now follows:
‘Kilmihil or Kilmichael, a parish in the Barony of Cloderalaw, County of Clare and Province of Munster, 8 miles from Kildysart, on the road from Kilrush to Ennis, containing 3,794 inhabitants of which number 79 are in the hamlet. It comprises 8089 statute acres about two thirds of which consist of arable land of medium quality and the remainder of mountain pasture. There is also a considerable portion of waste and bog. Fairs are held in Kilmihil on May 19th, July 18th and September 29th and a court for the Manor of Crovreahan is occasionally held in Kilmihil by the seneschal in which small debts are recoverable. The parish is in the diocese of Killaloe, the rectory is impropriate in the representatives of Lord Castlecoote and John Scott Esq. and the vicarage forms part of the union of Kilfarboy. The tithes amount to £192 of which £62-15s-41/2d is payable to John Scott Esq. and the remainder to the Vicar. In the Roman Catholic divisions it is the head of a union or district which also comprises the parish of Kilmacduane. About 120nm children are educated in two private schools. The ruins of the old church still remain in the burial ground.’

Another description of Kilmihil in 1845 from the Parliamentary Gazeteer of Ireland, 1845
KILMICHAEL, vulgarly KILMIHILL, a parish, containing a hamlet of the same name, in the barony of Clonderalaw, 8¼ miles west-north-west of Kildysert, co. Clare, Munster. Length, 5 miles; breadth, 4½; area, 18,772 acres, 3 roods, 2 perches,-of which 142 acres, 2 roods, 15 perches are water. Pop., in 1831, 3,794; in 1841, 5,080. Houses 860. Area of the village, 11 acres. Pop., in 1831, 79; in 1841, 118. Houses 23. Fairs are held on May 19, July 8, and Sept. 28. The parochial surface consists of arable and pasture land, intermixed with bog and mountain; and is washed and drained by the Creegh and Doonbeg rivers. The highest ground is in the north, and has an altitude of 554 feet; and the highest level of the Creegh rivulet, within the north border, is 493 feet.-This parish is a vicarage, and part of the benefice of KILFARBOY, in the dio. of Killaloe. The vicarial tithes are compounded for £80 4s. 1d., and the rectorial for £118 3s. 1d., and the latter are impropriate in Lord Castlecoote and Bindon Scott, Esq. The Roman Catholic chapel has an attendance of 900; and, in the Roman Catholic parochial arrangement, is united to one or two chapels within the benefice of Kilmurry-Clonderalaw. In 1834, the Protestants amounted to 12, and the Roman Catholics to 4,068; and two hedge-schools had on their books 82 boys and 41 girls. The Kilmichael and Cooreaclare dispensary is within the Kilrush Poor-law union, and serves for a pop. of 7,635; and, in 1839-40, it expended £95 12s. 10d., and made 2,400 dispensations of medicine.
The origin of the name “Kilmihil”
Kilmihil is a transliteration of the Gaelic Cill Mhichíl which means “The church of St. Michael”.
St. Senan and Kilmihil
Tradition credits the founding of a church here to St. Senan in honour of Michael the Archangel. During the reign of Pope Galasius (A.D. 492-496) an apparition of the Archangel took place on the summit of Mt. Garganus in Apulia in Italy. This apparition and the founding of the church in Kilmihil both took place during St. Senan’s lifetime (488A.D. – 554A.D.). After visiting Rome about 530 A.D. he returned to Ireland wishing to foster devotion to Michael. While travelling from Scattery Island to Doolough he stopped in Kilmihil where he founded the church.
John Breen
In April 1920, after Sunday mass, an attack took place on the R.I.C. patrol in the village of Kilmihil. A local man, John Breen, was shot dead. Sergeant Carrol, R.I.C. was also killed and Constable Collins was severely wounded. Several civilians were injured in a conflict between police and people. There are reports of panic as men, women and children fled in all directions. John Breen was aged 22. He became a member of the Volunteers in 1917, with the formation of the Kilmihil Company. He became one of its first officers. A monument to his memory has been erected in Kilmihil.