East Harnham, upstream of Britford, was a tithing of Britford parish until All Saints' church was built there in 1854, and a district chapelry created for it the next year.
In the vicinity of Britford, East Harnham was previously part of Britford parish but became a separate entity with the construction of All Saints' Church in 1854, followed by the establishment of a district chapelry for the area the next year.