Wherstead is one of the nine parishes of the Shotley peninsula, the neck of land between the Orwell and Stour estuaries in SE Suffolk. The peninsula belongs to the Sandlings, and the sandy soils support arable farming in a landscape that rises fairly steeply from the Orwell estuary in the E. Wherstead is now just outside the loop of the A14 that forms the southern and western sections of Ipswich's outer ring road, cutting through Wherstead Park before crossing the Orwell on the spectacular Orwell bridge. The village itself consists only of a few houses clustered close to the stable block of Wherstead Park, which is now occupied by the offices of EON Energy, the company that runs Powergen. The church lies between this cluster and the Hall, half a mile to the E. According to Laverton, 'Wherstead church stands on one edge of a very large rectangular embanked enclosure of unknown date, and nearby is a Roman site that might have some connection with the supposed Roman river crossing of Downham Bridge, but neither of these is visible except in aerial photographs.' The entire peninsula displays evidence of continuous settlement going back to the Neolithic period.

St Mary's consists of a W tower and a nave and chancel under a single roof, the nave only marginally wider than the chancel and the two separated by a 19thc. arch-braced truss supported on corbels. The nave and chancel walls have been rebuilt and supplied with gargoyles at the top of their lateral walls, but the 12thc. origin of the nave is indicated by the two lateral doorways (the N blocked and the S under a 19thc. flint and timber porch). The chancel has a 19thc. N vestry and S priest's doorway, but this part of the church appears to date from the 13thc., to judge from the piscina. Most of the windows of the nave and chancel are 19thc. replacements, with geometrical tracery found in both nave and chancel alongside some plain lancets in the chancel only. The tower arch is tall with a chamfered arch dying into plain jambs without capitals. The tower is tall and slender with diagonal buttresses decorated with flushwork, a polygonal SE bell stair and a Perpendicular W window. There was a bequest of two marks by William Brown in 1455 for building the tower, and a gift for a new bell in 1469. The upper section has been rebuilt or raised and given pointed segmental bell-openings with reticulated tracery. The battlemented brick parapet may be 18thc. and has eight crocketed pinnacles. The church is a typical Suffolk build of flints (some knapped), stone rubble and septaria. The rebuilt upper section of the tower includes a high proportion of septaria and some brick. The restoration largely responsible for the present appearance of the church was by Phipson in 1883-84. Between 1600 and 1902 a large copper ball stood on a pole at the top of the tower as a navigational aid to shipping on the Orwell. The only Romanesque sculpture in what is essentially a 19thc. church is found on the two nave doorways.

Edmund, a free man of Robert fitzWymarc, held Wherstead as a manor before the Conquest, with one carucate of ploughland and three acres of meadow. In 1086 it was held by Fulcric from Count Alan. Another manor, of forty acres, was held by Thorsten before the Conquest. This included a salt-pan and was held by Aelfric the priest from Count Alan in 1086. A third holding here was that of Toli before the Conquest, like Edmund’s it was of one carucate of ploughland and three acres of meadow. This was held by Swein of Essex in demesne in 1086.

Benefice of Holbrook, Stutton, Freston, Woolverstone and Wherstead.

David Elisha Davy's notes on the church, made in 1818 and 1843, note that the capitals of the S doorway were almost worn away even then, and that it was covered with a thick layer of whitewash. The advanced forms of chevron found on this doorway are uncommon in Suffolk, although a comparison for the simpler point-to-point type can be seen at St Mary’s, Benhall near Stowmarket, some 18 miles to the NE. A date in the 1160s seems likely for this work.