Granston includes the estate of Tregwynt, whose papers are held by the Pembrokeshire Record Office.
In the 14th century Sir William Horton of Tregwynt married the heiress to Candleston Castle.
 The Tregwynt Hoard, from the Civil War, was found at Tregwynt Mansion in 1996.
The present Grade II*-listed manor house and extensions date from the 18th century.

Tregwynt mill (Melin Tregwynt) dates back to the 17th century when it served the surrounding area’s sheep farming.
It is still in operation, employing about 30 people,
and in 2012 celebrated 100 years as a family business, now weaving for a global market.
The mill featured in a BBC2 Wales Made in Wales episode in December 2012.
Granston includes the estate of Tregwynt, whose papers are held by the Pembrokeshire Record Office. In the 14th century Sir William Horton of Tregwynt married the heiress to Candleston Castle.  The Tregwynt Hoard, from the Civil War, was found at Tregwynt Mansion in 1996. The present Grade II*-listed manor house and extensions date from the 18th century.
Tregwynt mill (Melin Tregwynt) dates back to the 17th century when it served the surrounding area’s sheep farming. It is still in operation, employing about 30 people,
and in 2012 celebrated 100 years as a family business, now weaving for a global market. The mill featured in a BBC2 Wales Made in Wales episode in December 2012.
Granston