The estate of Coghill is in the parish of Watten.
The proprietors of the small estate of Coghill and Gersay in Watten, now part of the estate of Watten, were, so far as is known, the only county landholders who bore the designation "of that Ilk".
The first, apparently, of this family was Alexander Coghill "of that Ilk", who flourished previous to 1630, in which year he was succeeded by his son, David.
David Coghill got a charter in 1630 from William, Lord Sinclair, and another charter in 1638 from John, Master of Berriedale. In 1650 he was infeft in Scottag, on a charter from the Earl of Caithness.
Barbara Coghill, daughter of "Coghill of that Ilk", who married James Oswald, a Bailie of Wick, may have been the sister or perhaps the daughter of David Coghill.
Thomas Coghill of Coghill and Gersay, the son probably of David, obtained a precept of clare constat from the Earl of Caithness.
In 1671 David Coghill of Coghill got a charter from the Earl of Caithness, confirming a disposition to him by David Coghill of Coghill; and it is presumed that he was the son of Thomas, and grandson of the first David.
About the end of the century (1698) the lands were acquired by Alexander Manson of Watten.