Long Marston is a small village in the Dacorum district of W Hertfordshire, 3 miles NW of Tring and 5 miles E of Aylesbury, over the border in Buckinghamshire. The church dates from 1882-83 and is by Carpenter and Ingelow. It replaced a dangerously dilapidated medieval church on a site to the S, of which the 15thc tower remains. The site of the old church was saturated with water from a moat dug to drain the former manor house, and the new church was therefore built on a fresh site. The present church, built of knapped flint, consists of a tall nave and chancel under a single roof with a lean-to N aisle whose 15thc arcade piers were taken from the parish church of Tring (restored 1880-82), when Carpenter and Ingelow replaced Tring's piers with new ones. The capitals stayed in Tring. The chancel has an organ room to the N, and behind the organ, set in the N wall, are medieval stones taken from the old church. A W tower was planned by the vicar, W. C. Masters, but was not built, and in 1907-08 a W porch and vestry were added by William Huckvale instead. In 1995 a vestry, kitchen and lavatory were added at the W end of the aisle.

In the Middle Ages, Long Marston was always part of the manor of Tring, held by Ingelric before the Conquest and by Count Eustace of Boulogne in 1086. Eustace's heir was Maud, King Stephen's queen, and she gave Tring to his foundation of St Saviour's, Faversham, in whose possession it remained until the Reformation, when it was granted to Christ Church College, Oxford. The church remained in the hands of the Abbot of Faversham until 1294-95, when the abbot granted the advowson to King Edward I. Until the 19thc, Long Marston was a Chapel of Ease to Tring parish, but in 1867 a new parish of Long Marston was created, in the Diocese of Rochester (the advowson remaining with Christ Church College). Ten years later the new diocese of St Albans was founded and both Long Marston and Tring parishes became part of this.

The stones tell is little about the medieval church, as there seems to be no record of their original locations, they are broken into small fragments and that are coated with whitewash. The point-to-point chevron is probably from a doorway of the second half of the 12thc.