Preston St Mary is in the rolling arable land between Bury St Edmunds and Sudbury, towards the W of the county. The nearest town is Lavenham, 2 miles to the W. Preston stands on a low hill above a stream to the E that runs S into the river Brett. It is an attractive village; its main street occupied by houses and a pub, with the church at its southern end, facing the street and alongside the hall. St Mary's has an aisled nave with a N porch, chancel with N vestry and W tower. The nave has a 15thc. clerestory and three-bay aisles with 15thc. windows. The N porch is 15thc. too, but very elaborate with flushwork decoration, niches on the buttresses and a battlemented parapet. The chancel is 14thc. in its details, with one reticulated N window and flowing tracery in the E and S windows. The N vestry is 19thc., with a N window with Perpendicular-style tracery. The tower has diagonal buttresses to the E, a polygonal SE bell-stair and a battlemented parapet with gargoyles below. The W face has a 15thc. doorway with kings as label stops and niches to either side and above for statuary. The bell openings are two-light reticulated with triangular heads. The nave, aisles and chancel are of flint, septaria and reused brick or tile - a typical Suffolk mixture. The tower is of roughly-knapped flints. The church contains an important early Romanesque font.

Preston was held as a manor by Wulfwaerd, a free man under Stigand, before the Conquest; the manor including 2 carucates of land and 9 acres of meadow. There were also three free men here, commended to Wulfwaerd, who held 23 acres between them. In 1086 these lands belonged to Roger de Poitou. There were also three carucates here held before and after the Conquest by a free man of St Edmundsbury Abbey. This holding included 3 acres of meadow and a church with 7 acres of land. A portion of the church of Preston was granted to the Priory of Benedictine nuns at Wix (Essex), possibly in the 12thc. By the beginning of the 13thc., however, the church was held by the Austin canons of Holy Trinity Priory, Ipswich and this holding is confirmed by the Taxation Roll of 1291. In 1335 the priory obtained land at Preston too.

Benefice of Lavenham with Preston.

The font includes interlace designs, simple flowers in squares related to chip-carving and stringy acanthus foliage motifs, all suggesting a date in the first two decades of the 12thc. The closest comparison for this work is on the S doorway tympanum at Poslingford, which is rather more accurately drawn. The carving here at Preston is accomplished, even if the fields are not always very precisely laid out. The fonts at Little Thurlow, Kettlebaston, Hawkedon and Great Bricett are all similar in having box-shaped bowls with shafts at the angles and relief carving on the faces, which seems to be a characteristic Suffolk type. Those at Hawkedon and Little Thurlow are by the same workshop as each other and have foliage designs on their faces, but are rather later than Preston's. The font at Kettlebaston may be contemporary with Preston, but it is cruder work and only has geometrical carving. The Great Bricett font has a variety of arcading on its faces, including some intersecting arches, but cannot be closely linked to the Preston font. None of these comparisons has a square inner basin. Bond (1908) identified a NW Norfolk group comprising Shernborne, South Wootton, Sculthorpe and Toftrees, to which he connected the Preston font as 'a clumsy copy'. Drake similarly linked it to Sculthorpe and Toftrees.