Since the sixteenth century, when the general anglicization of Gaelic names began, at any rate for official purposes, the surname Ennis has been closely associated with Co. Kildare and the adjoining parts of Meath and Offaly. Ennis was formerly O'Hennis, which is Ó hAonghuis in Irish. That is a variant of Ó hAonghusa i.e. O'Hennessy. Those septs which concern us in dealing with Ennis are O'Hennessy of Moyfenrath, a Meath barony contiguous with north Kildare, and O'Hennessy of the barony of Philipstown, Co. Offaly, which adjoins both counties Meath and Kildare.

In both those areas we find Ennis, then written Enos, Ennous (to mention only two of the many variants) very frequently in sixteenth century records; and in the next century the “census” of 1659 returns it as one of the most numerous names in four baronies of Co. Kildare and in one of the baronies of Co. Offaly adjoining Co. Kildare. The spellings in that document are Ennis, Ennos, Ennes and Enos.

By that time it had to some extent died out in Co. Meath where, however, it is perpetuated in the placename Ennistown in that part of the county associated with the sept of O'Hennessy. This occurs in a Fiant of 1568 as Enostown. As Enos it was well known in Dublin as the records of the city guilds from 1550 to 1650 show.

The form Enos is, I think, now obsolete but it was used at least as late as 1720, as we know from a Registry of Deeds will of that date. Before the general relinquishment of the Gaelic prefixes Mac and O, Ennos was often written O'Hennos. MacEnnos also occurs in similar records. In Ulster this may well be an English official's mis-spelling of MacGennis, but when it is found in Leinster it is more probably an error for O'Hennos: much confusion existed — not among the Gaels themselves but among officials with no Irish background-between Mac and O. This question has been discussed elsewhere in this series and need not be further considered here.

The Ennis family suffered under both the Cromwellian and Williamite regimes. In 1642 three of the name were attainted-two of Grennagh, Co. Wicklow, one of Hacketstown, Co. Carlow, and also James Ennis, of Clane, Co. Kildare. A Lieutenant James Ennis was a Royalist soldier of note of that time. In the next generation we find John Ennis, who had previously risen to the rank of major in the French army, as lt. colonel of Edmond Butler's Infantry Regiment in James II's Irish army; and following their defeat Edmund Ennis, of Athy, Co. Kildare, was outlawed as a Jacobite.

In Ireland Ennis must not be confused with the Scottish name Innes. It should be added that as a surname it has no relation to the town of Ennis; though early English records, e.g. the Hundred Rolls (1273) contain the name del Ennesse, which Reaney states is derived from the Irish word inis, island, as is the town of Ennis.

Two ecclesiastics of the name are notable: Rev. Walter Enos, S.T.D. author of Survey of the Peace (1646) and a severe critic of Clanrickarde; and Dr. John Ennis, the Dublin parish priest prominent for his part in the opposition to those bishops who were not in favour of the establishment of the Queen's Colleges in 1848.

(Celtic) 1 contraction of MacGennis, q.v.

2 Dweller at an Island or Riparian Meadow [Irish inis = Gaelic innis] Cp. Innes.

Ó hAonghuis This is a variant of Ó hAonghusa (O’Hennessy) of Moyfenrath on the border of Meath and Westmeath. It was well known in that and adjacent areas in its earlier forms Ennos, Enos etc. It has no connexion with the town of Ennis. SIF 64

(Celtic) 1 contraction of MacGennis, q.v.

2 Dweller at an Island or Riparian Meadow [Irish inis = Gaelic innis] Cp. Innes.

(Celtic) 1 contraction of MacGennis, q.v.

2 Dweller at an Island or Riparian Meadow Cp. Innes.

(English, Irish) Dweller at the island or secluded place; grandson of Aonghus (one choice).

A contraction of the Irish Mac Gennis.

(Celtic or Gaelic.) Local. An island or peninsula, made so either by a fresh water river or the sea. Ynys in the Welsh.

From Enys; a location name in Cornwall.