The surname Trefusis was first found in Cornwall where they held a family seat as Lords of the Manor of Trefusis in the parish of Milor.
"The ancient manor of Trefusis has been so long in the family of Trefusis, that no prior claim is known to have existed. It is generally believed, that this property belonged to this family long before the Conquest. But however dubious this fact may appear, it seems to be fully ascertained, that the Trefusis family can be traced as resident at Trefusis in Milor, four generations before the year 1292, though not with those titles with which the family has since been dignified." 1
"The Trefusis family had formerly a seat in this parish, and two manors still belong to Lord Clinton; namely, Treveses and Treworac." 1
"The manor of Trelizike or Trelisick [in the parish of St. Erth, Cornwall] belonged, in the reign of Edward IV. to the lands of Otho de Trefusis. This fact he learned from an ancient deed that fell under his inspection. From the descendants of Trefusis it passed to the Smiths, and in the reign of Charles II. was the property of Sir James Smith." 1
The family held another manor in the parish of St. Keverne. "The manor of Trythnance, which belonged to the Trefusis family, was purchased of them in the year 1786, by Sir William Lemon, the present proprietor." 1
