It lies 2 miles (3 km) east of Truro, on the eastern side of the Tresillian River.

[2] It was formerly the churchtown of the small parish of Merther, and also the site of a manor house and medieval chapel dedicated to St Cohan (also spelt Coan).

Eglosmerther is a Grade II listed building on the site of a manor house, and the barton was held in 1311 by the Reskymers.

[11] The ruin of St Cohan's church is grade II listed and was built of slatestone walls with granite dressing.

The 12th-century Pentewan stone font, 17th-century polygonal oak pulpit and bells were removed to the new church, and St Cohan's became a mortuary chapel.