The patronage of the church was originally given to the monks of St Mary's Abbey in York, then at the Dissolution, it was offered to the Crown.

The churchyard at St Mary's has a plague pit and the graves of two soldiers from Waterloo, and it also used to house the original Richmond School building.

[6] Clarkson states in his History of Richmond, that Holy Trinity was too small to accommodate the growing population and so a "Low Church, situated on the declivity of the hill" was built.

However, until The Reformation, both churches were lesser in terms of religious importance in comparison to Easby Abbey (St Agatha).

[10][11] Parts of the nave and aisles date back to the middle of the 12th century, but the varied renovations have left a much altered church from what is believed to be a cruciform building originally.

[14][15][16] The tower is supported on each of its four corners by buttresses and internally used to have the arms of the Nevill family;[17] The Earl of Westmorland (Ralph Neville), was granted the Honour of Richmond in 1399 by Henry IV, and he set about improving the church among other things.

[19] Before The Reformation, the windows in the church displayed images from the scriptures, but these were later viewed as "superstitious" post-Reformation and so fell to decay or were replaced with ordinary glass.

They date from the early sixteenth century and show a sow playing the bagpipes for two piglets, and a dragon stealing a goose.

[28] More renovations took place in 1897 under C. Hodgson Fowler, the most notable of which was the installation of a steep pitched roof covered in slates.

[21] In March 2017, the bells were replaced with modern castings and housed at the same height to make the bellringing easier and to safeguard the tower.

St Mary's had been the official church of the garrison and regiment since the early 19th century, and the chapel has colours hanging from the rafters, mementoes from the First World War and an altar rail dedicated to two lieutenants killed in 1915 and 1917.

[37] As the Green Howards have been subsumed into the modern day Yorkshire Regiment, the Royal Lancers have adopted the chapel for their services.

[38] The chapel and the interior of the church are adorned with memorials to members of the armed forces who either died in action or represented the Green Howards in some way (IE senior officers).

[39] A stone tablet, set into one of the walls, commemorates the dead from 1916 to 1919 and is listed as the Yorkshire Regiment, which was how the Green Howards were sometimes known.

[44][45] The graveyard also contains a plague stone (one of two in Richmond),[note 1] which marks the spot where the bodies of 1,072 people who succumbed to the Black Death between 1597 and 1599, were buried.

[49] In 1861, the Bishop of Ripon ordered that a tombstone be removed from the grave of a recent burial as it contained the Latin phrase Miserere mei deus, which, at the time, was contrary to what was allowed as it was viewed as a "Purgatorial text".