Originally built as a dependent chapelry in the parish of Leighton Buzzard, Eggington became a parish in its own right in 1810. The church consists of a nave around 43 feet long by 20 feet and a chancel adding around 14 feet by the same width.
There is a south porch and vestry and organ chamber to the north of the chancel and a small bell cupola over the west end of the nave. The church was badly damaged by fire in 1876 and much of the church dates from restorations of 1882-3.
The nave is of Bedfordshire Ironstone and has two windows on the south side on either side of the porch.
These are both of two coincident lights under pointed arches.
The eastern window has subordinate trefoil tracery below quatrefoil designs in the head of the individual lights.
The western window also has subordinate tracery with a trefoil design below trefoils in the heads of the lights.
The south porch is modern being of open woodwork on a masonry base.
The doorway itself dates from the same period as the nave.
The west end of the church has angle buttresses and a central buttress.
The round west window is modern featuring encircled trefoil designs in the quadrants of trefoiled arches with at quatrefoil design in the centre.
The bell cupola above dates from the 1882-3 restorations and is of wood and shingles with a tiled roof in keeping with the rest of the church.
The north aisle follows a similar pattern to the south with two windows matching those on the south surrounding the now blocked north doorway.
The vestry and organ chamber on the north side of the chancel has a priest’s door and single window to the east.
The east window is formed of three individual lancets with a taller central lancet under a common hood mould.
On the south side, the chancel has two modern single lancet windows in pointed arches with elongated trefoil cusping surrounding a priest’s door under a two centred arch.