[5] Laugharne was a seaport from the early Middle Ages [6] and the first owners of Island House traded goods from the adjoining Gosport Harbour[7] at the head of the Corran navigation.

[13] They feature members of prominent families including Vaughan of Golden Grove and Mansel of Margham along with Rhys Prydderch of Laugharne, Jasper White's great-great-grandson and High Sheriff in 1608.

His son James' successor, Evan Thomas of Tremoilett, moved to Island House just before the Lordship of Laugharne was sold to Sir William Russell, who garrisoned the adjacent castle for the Royalist cause in the Wars of the Three Kingdoms.Before the castle's surrender in November 1644 to Parliamentary forces under Major-General Rowland Laugharne [14] its gatehouse was subject to a sustained heavy bombardment and Island House suffered significant collateral damage as a consequence.

– The Antiquities of Laugharne and Pendine Mary Curtis [2]A date of 1658 is engraved into the lintel of the yard door, indicating some rebuilding having taken place at this time, perhaps reconstruction following the Civil War damage.

A recent study has shown that Island House was passed down via a series of wealthy and often powerful owners, as a constituent part of the estate originally held by James Prydderch in 1595.

Mary's accounts book for 1835–1836 records the cost of taking a sedan chair to an assembly at The Globe Inn, only 100 yards from Island House, which speaks to both the community's prosperity and her own affluent lifestyle at that time.

[20] By 1871 a reverse in the township's fortunes was noted, reflecting the decline in its harbour traffic which was further accelerated by the arrival of the railway at nearby St Clears in 1854, [21] a direct competitor to the sea-carrying trade: As for Laugharne, nearly all the wealthy and ancient families are gone.

[23] Even in the years of economic recession and profound social change which followed WW1, two full-time gardeners were still employed by retired Indian Army major, Claude Vivyan Congreve, who took up residence at the turn of the century and died in 1923.

His widow Mary, an accomplished musician, was responsible for organising monthly dances, concerts raising funds for the church, dramatic productions and indeed most of the town's entertainment between the wars according to her neighbour Lt Colonel R. A. Tucker, whose mother had accompanied the Congreve family when they moved to Laugharne from London.