The Thomas Gifford ⁵  summary  in 1716 shows that the Earl of Morton was the Grand Lord, or virtual owner of the Shetlands.  In reality the Earl of Morton held the land by Royal favour.  He sublet the whole of Shetland to various Lairds in return for a fee. 

Dunrossness was sublet to 4 major Landlords, namely:

Charles Stuart of Bigton who held lands mostly around Bigton and Scousborough, with other bits of land dotted around here and there. He also had an enormous holding in Yell

John Scot of Scotshall had large holdings in the Scatness and Exnaboe region.

Laurence Bruce of Sunburgh had holdings at Scatness, Clumlie etc.

Robert Sinclair of Quendall had holdings there and in the surrounding area.

The map below has the above places on it, but the exact boundaries between the land owned by these landlords is not shown.

See map of Dunrossness.