From The Official Guide, Salisbury & Wilton Rural District, Wiltshire, c.1950:
South Newton
Covering an area of 3,000 acres, this parish is situated on the River Wylye and is of ancient origin. The name derives from the fact that the earlier village South Newton has been divided, part remaining under the jurisdiction of the Borough of Wilton, and the remainder, being given the name of “Without” being formed into a separate parish, which is just under two miles from Wilton. The other part of the village, which remains within the Borough of Wilton, is now called “South Newton Within.”
The parish church is dedicated to St. Andrew and contains some Norman work.