Ashby is in Lothingland, the Nernmost hundred of Suffolk. It is a tongue of land enclosed by the Waveney, which turns N after leaving Beccles so that it may reach the sea at Yarmouth rather than Lowestoft. The land here is low-lying and arable, and its villages have usually managed to resist encroachments by their giant neighbours to the N and S. Ashby church now stands alone in farmland, 0.4 mile S of a small, dispersed cluster of houses that is all there is of Ashby village. The medieval village was in the land immediately to the N of the church, and was deserted byc.1600. N of the present village is Ashby Warren and the Fritton Decoy - a lake fitted with nets for catching wild duck. Both the warren and the decoy appear to date from the 16thc.

St Mary's is a flint church with a long nave and chancel in one, covered with a thatched roof, and a round W tower. The tower is, in fact, only round for about 3m at the base; above this it is octagonal. The lower part has a pointed 13thc. W lancet, and the tower arch is an 18thc. Gothic construction with an ogee head. The upper section of the tower has brick quoins, tall brick bell-openings, and a brick embattled parapet. The nave and chancel are 13thc. to judge from the plain lancets in both, the doorways and the piscina. Y-tracery and Perpendicular windows have been added. There is no chancel arch. The church has largely escaped restoration beyond repairs when necessary. There were extensive repairs to the tower in 1924, and restoration of the tower roof and the bell chamber in 1957. The most recent of these came in 1987 when the hurricane of 16th October caused such damage to the roof that re-thatching and recapping of the entire roof was needed. The work was complete by May 1989. The only Romanesque sculpture is the Purbeck font.

The area was occupied in the Neolithic period; flint tools have been found around Fritton Decoy to the N of the village. No signs of Roman occupation have been found, but an early Anglo-Saxon settlement is certain in view of the discovery of the Ashby burial boat, discovered in Ashby Dell between the lake and the church in 1830. It has been dated c.400-450 AD. Ashby is not mentioned by name in the Domesday Survey, but landholders named in the reign of Henry II were Robert le Pene, Alice Smethe and Osbert. The lords of the manor took their name from it; the earliest known being Geoffrey Askeby (c.1210 and John Askeby (c.1241). By 1312 the manor had passed to the Inglose family of Golosa, near Loddon; in that year John de Inglose presented Galfridus de Inglose to the church as rector. In 1397 the manor of Ashby was held by Nicholas Wychingham, who leased the house to John Atte Grove. In 1400 it was held by Thomas Ashman, but in 1402 it was back with the Inglose family, in the person of Anna, wife of Henry Inglose.

Benefice of Somerleyton, Ashby, Fritton, Herringfleet, Blundeston and Lound.

Imported Purbeck and Sussex marble fonts are common in Suffolk.