Branches of Clan Sinclair
Earls of Caithness (Chiefs)
The Earls of Caithness are the chief line of Clan Sinclair. Their lineage was established when William Sinclair, 1st Earl of Caithness, exchanged the Norse earldom of Orkney for Caithness in 1470. From their seat at Castle Sinclair Girnigoe in Wick, the Caithness Sinclairs ruled over one of the most powerful territories in the far north of Scotland. The title has passed through various cadet branches, including those of Murkle, Keiss, Rattar, and Mey, preserving Sinclair leadership through periods of uncertainty. The current chief is Malcolm Ian Sinclair, 20th Earl of Caithness.
Barons of Roslin (Rosslyn Line)
The Sinclairs of Roslin are the earliest well-documented Lowland line, dating to the 13th century. They gained prominence through Sir William St Clair, who acquired the Rosslyn lands and built Rosslyn Castle. His descendant, William St Clair, 1st Earl of Caithness, divided his estate between sons, giving Rosslyn to one and Caithness to the other. The Roslin Sinclairs are most famous for building Rosslyn Chapel, a renowned Gothic masterpiece rich in Masonic symbolism. The male line ended in 1778, but their cultural legacy endures.
Lords Sinclair (Dysart and Ravenscraig Line)
This cadet branch was established when Henry Sinclair was created Lord Sinclair in the 15th century. Based at Ravenscraig Castle in Fife, they descended from the Roslin line and played an active role in Lowland politics. The Lords Sinclair title was passed to the Sinclair of Herdmanston line in the late 17th century and has continued to the present day, with the current holder sitting in the Scottish peerage. The title remains a link between the Highland and Lowland branches of the clan.
Obscure or Nonactive Branches
Sinclairs of Herdmanston
Among the earliest Sinclair families in Scotland, the Herdmanston branch received lands in East Lothian in the 12th century. Some scholars debate whether they share a common ancestor with the Roslin line or arrived independently. They held significant local authority and were integrated into the Lords Sinclair lineage by marriage in the 17th century. The line became extinct as a distinct branch shortly afterward.
Sinclairs of Ravenscraig
Originally a part of the Lords Sinclair lineage, this branch maintained the family seat at Ravenscraig Castle in Fife until the estate was sold in the 19th century. While once prominent, especially in the 15th and 16th centuries, this designation faded as the Dysart and Herdmanston lines merged.
Sinclairs of Longformacus
A Border branch established in Berwickshire during the 14th century, descending from the Herdmanston family. The Longformacus Sinclairs gained baronet status in the 17th century and held lands in East Lothian. Over time, the family merged with the Sinclair-Lockhart line, and the baronetcy became dormant.
Sinclairs of Murkle
This northern branch in Caithness descended from a younger son of the 4th Earl of Caithness. The family produced John Sinclair, 8th Earl of Caithness, in 1698, but the male line failed in 1765. Their estates and influence were absorbed by other cadet lines.
Sinclairs of Keiss
George Sinclair of Keiss defended the Sinclair claim to the Caithness earldom in the 1670s when another branch attempted to transfer it to the Campbells. After a legal and military struggle, George was confirmed as 7th Earl of Caithness, and the Keiss line merged with the chief line.
Sinclairs of Greenland and Rattar
A cadet line from the 4th Earl of Caithness, this family held lands in northern Caithness. William Sinclair of Rattar was confirmed as 10th Earl of Caithness in 1768, thus merging this branch with the chief line.
Sinclairs of Mey
Founded by William Sinclair, younger son of the 4th Earl of Caithness, this branch inherited Castle Mey. Sir James Sinclair of Mey was confirmed as 12th Earl in 1790, and the Mey line became the new chief line. It later merged fully with the earldom.
Sinclairs of Ulbster
A distinguished Caithness line that produced Sir John Sinclair of Ulbster, 1st Baronet, a noted Enlightenment reformer. His descendants became Viscounts Thurso. Although now part of the British peerage, the branch has ceased to exist under the Sinclair of Ulbster name.
Sinclairs of Freswick
This minor branch held Freswick Castle and built Freswick House. Known for colorful characters, including legal disputes over window taxes, the line eventually died out or was absorbed by other families.
Sinclairs of Stemster and Dunbeath
This branch produced multiple baronets of Nova Scotia in the 17th and 18th centuries. Though once prominent, especially around Dunbeath Castle, the line did not survive past the 18th century.
Sinclairs of Assery
A minor 17th-century branch descended from an illegitimate son of the Murkle line. The estate and lineage faded by the 18th century and are now obscure.
Sinclairs of Lybster
An offshoot of the Caithness earls through illegitimate descent, the Lybster branch existed briefly in the 17th and early 18th centuries. The line ended with no male heirs.
Sinclairs of Scotscalder
Derived from the Sinclairs of Hoy, this branch held Scotscalder estate and produced the short-lived Achingale and Newton line. It faded from records after the 18th century.
Sinclairs of Geise
A minor branch in northeast Caithness, possibly connected by marriage to the Sutherland family. The estate passed to others by the 18th century, ending the Sinclair connection.
Sinclair Sutherland of Brabster
A hybrid family line created by marriage between Sinclair and Sutherland descendants. They held the Brabster estate but later dropped the Sinclair name.
Sinclairs of Barrock
A 17th-century cadet of the Canisbay line, this family briefly held Barrock estate. By the 19th century, the line became extinct or merged through marriage.
Sinclairs of Stirkoke
A lesser Border branch that disappeared from records after the early 18th century. Likely merged or died out without male issue.
Sinclairs of Dun
Possibly descending from a younger son of the 2nd Earl of Caithness, this branch held lands in Watten parish. They faded in the 18th century with uncertain succession.
Sinclairs of Forss
A western Caithness branch, reportedly descended from David Sinclair of Dun. They became extinct or absorbed into other families in the 18th century.
Sinclairs of Achingale and Newton
A short-lived 18th-century cadet of the Scotscalder line. It ended within two generations and is now remembered only in genealogical records.
Sinclairs of Hoy and Oldfield
An early form of the Scotscalder branch. The name ceased to be used after the family acquired new estates. No separate line exists today.
References (APA Format)
Henderson, J. (1884). Caithness Family History. Edinburgh: David Douglas.
Paul, J. B. (1910). The Scots Peerage (Vol. VII). Edinburgh: David Douglas.
Clan Sinclair Association USA. (n.d.). Clan History. Retrieved from https://www.clansinclairusa.org
Rosslyn Chapel Trust. (n.d.). Sinclair Family of Rosslyn. Retrieved from https://www.rosslynchapel.com
Fiona Sinclair. (n.d.). Caithness Sinclair Genealogies. Retrieved from http://www.fionamsinclair.co.uk/genealogy/caithness
Historic Environment Scotland. (n.d.). Ravenscraig Castle. Retrieved from https://www.historicenvironment.scot