From Stamps of the World
Delvin (Irish: Dealbhna or Dealbhna Mhór) is a town in County Westmeath, Ireland which is located on the N52 road at a junction with the N51 to Navan. The town is 20 km (12 mi) from Mullingar (along the N52). The word Delvin comes from Delbhna. That tribe settled in what is present-day Delvin, along with a branch of the Soghain, in Tricha céd na Delbna Móire agus na Sogan.
Delvin Castle (or Nugent Castle), now a ruin, was built in 1181 by Hugh de Lacy, Lord of Meath for his brother-in-law, Gilbert de Nugent. De Nugent came to Ireland with de Lacy in 1171 and settled on some land in Delvin. De Nugent was granted the title Baron of Delvin within the Lordship of Meath, a title now held by the Earl of Westmeath. The ruins of Nugent Castle remain near the center of the town. A second castle was built several centuries later, hundreds of metres from the centre of the Delvin settlement of that time.