Coordinates: 50°16′41″N 4°59′42″W / 50.278°N 4.995°W
Tresillian (Cornish: Tresulyan) is a small village in mid Cornwall, England, United Kingdom. It is three miles (5 km) east of Truro on the A390 road. Tresillian means "a place of eels" in the Cornish language, according to a 19th-century writer. However, modern toponymists agree that the name in fact translates as "farm/settlement of a man called Sulyen" (a Celtic personal name from British: sulo-genos, "sun-born").
Tresillian was the home of Robert Tresilian, Chief Justice of the King's Bench between 1381 and 1387. A famous event of the English Civil War took place here in 1645. Thomas Fairfax sent a summons of surrender to Ralph Hopton who replied on March 8 that he was willing to negotiate terms. Fairfax agreed to negotiate and on March 10, 1645 both sides met at Tresillian Bridge. Hopton agreed to move his army to St Allen as a gesture of trust and goodwill allowing Fairfax to occupy Truro. The Wheel Inn at Tresillian is Grade II Listed building and is said to be to have been used as Fairfax's headquarters during the Civil War (Battle of Tresillian).