- TremaineA surname from Cornish.
- TrevithickA surname from Cornish.
- TresidderA surname from Cornish.
- TreffryA surname from Cornish.
- TregennaA hamlet in Veryan parish, on the south coast of Cornwall, England (OS grid ref SW9440).
- TreglownA surname from Cornish.
- TregoningA surname from Cornish.
- TrewarthaA surname from Cornish.
- TreweekA surname from Cornish.