The church is situated on the south side of , in a small burying-ground, separated from the street by a range of shops, and the east end abuts on .

This church is a rectory dedicated to St. Dennis, or Dionysius, the Athenian areopagite or judge, and the tutelar saint of France: and the addition of Back-church is given to it, because it is situate backwards, or behind a row of houses, to distinguish it from St. Gabriel's church, which stood formerly in the middle of . It was in the gift of the abbot and convent of Canterbury in the year , and is now in the dean and chapter of Canterbury. The old church was burnt down in .

The building consists of a nave and side aisles, a portion of the

The aisles have on each side of the church large windows with arched heads, and above them is a clerestory which has arches in blank on each side, enclosing circular windows; the east front is handsomely and chastely ornamented. The centre division contains a spacious circular headed window divided into compartments by stone work between pilasters of the Ionic order in pairs sustaining an entablature and pediment; the frieze is con. vex, and the entablature is broken above the window, its place being supplied by festoons of fruit and foliage. The aisles have each an entrance consisting of a lintelled doorway surmounted by a cornice resting on consoles (the southernmost being walled up), and above them are circular windows; the elevation is finished with a plain parapet. The tower contains an entrance in the south wall of its basement story, which forms the principal doorway to the church, and is approached from the street by a small porch; it has stories above the basement, in each of which is a window, the lower circular, the others arched ; the elevation finishes with a parapet pierced with a small arcade; an awkward turret of lead, ending in a diminutive spire, rises from the roof of the tower, but with no great elevation, and it is finished with a vane.

The interior is strikingly handsome; a portion at the west end is taken off by the tower and a vestry at the opposite side, the space between being divided by a gallery and forming on the ground floor a vestibule, covered by a gallery, over which is a spacious recess lighted by a large circular window, and containing the organ. The remainder of the church is made into a nave and aisles, by Ionic columns, and semicolumns on each side the former, sustaining an entablature; the shafts are unfluted, and the frieze enriched with acanthus leaves set upright, a favourite ornament of the architect. The cornice serves as an impost to the arched ceiling of the nave, which has a perfectly plain surface pierced laterally with arched openings above the clerestory windows, and adorned at intervals with pendants. The ceilings of the aisles are horizontal, and made by architraves corresponding with the columns, into square pannels. Besides the western entrance there is on the north side, and another at the east end; they are fronted by screens of oak, enriched with Corinthian columns, and covered with elliptical pediments. The altar screen consists of a centre and side compartments; the latter are ornamented with Corinthian columns in pairs, sustaining elliptical pediments; the screen has been tastelessly painted of a salmon colour set off with white mouldings, in a theatrical style. The wall above the altar is painted with cherubs, and a crimson curtain, and the semicolumns which are attached to the east wall, are painted to imitate lapis lazuli, with gilt capitals. The pulpit is of carved oak, and is erected against a pillar on the north side. There is no visible distinction between nave and chancel in this church.

The architect of the present building was sir Christopher Wren; the church was finished in , and the steeple in . The whole cost of this handsome church only amounted to The dimensions are, length , breadth , height , tower and turret feet. In the vestry is a rack, affixed to the wall, containing several syringes of brass, made to contain rather more than a gallon of water, resembling, in appearance, the modern garden syringe. They derive a considerable degree of interest from being the only mode of extinguishing fires, when they were constructed. At the sight of such instruments, no can be surprised at the total destruction of the city by fire, when such inadequate methods of extinguishment existed. In the western vestibule there is also a fireman's hat of leather; its form is exactly that of the Venetian morion.