The church, which was heavily restored in the 19thC, consists of a nave with a N aisle and a chancel, all of ashlar. The W tower is brick in its upper parts. There is a Romanesque N doorway with elaborately carved but badly worn arch orders, and a partly remodelled 12thC font.

There were two manors in the time of Edward the Confessor and they were worth 30s. In Domesday Book, the king had 5 carucates and the Count of Mortain also had 5 carucates. Nigel Fossard held both manors, and they were waste (VCH Yorkshire II, 197, 225, 320). Hervey, 'clerico de Killyngwicc' was among the witnesses to a charter of c.1175-1183 regarding the confirmation of a gift by William Fossard II to the nuns of Watton. (EYC II, 411). Some time between 1170 and c. 1182, Hervey of Kilnwick and 'Helia nepote ejus' witnessed a similar charter for Thomas de Everingham (EYC I, 55).

According to Pevsner and Neave (1995, 578) the church was largely rebuilt in 1871. Morris (1919) considered it badly restored. No relevant papers are held at the Borthwick Institute. As for the doorway capital with the sunken relief cross, this motif also occurs on the S nave doorway at Newbald (East Riding) on the first order, R side, one on each shaft. In comparison to the mass of crosses randomly positioned on the shaft of the fourth order at Newbald, they appear orderly. The N nave doorway at Newbald also has a similar pair of crosses. The form of the cross at Kilnwick-on-the-Wolds, sunk within in a circle, resembles one on the wall near the chancel arch at Bishop Wilton. Doorways at smaller churches quite often bear a single cross on a capital. When such crosses were carved is unclear, but perhaps they served some ritual purpose. Doorway may well have been places to pause and pray on entry, perhaps while touching the cross (Wood 2015, 73).

The term 'abstract beakheads' is used in the first edition of the Pevsner guide for this feature at Kilnwick, also at Bishop Wilton and Etton (1972, 293, 225, 192). In John Salmon's paper (1947), only bird- or animal-based motifs are discussed as beakheads. To say the 'abstract beakhead' is derived from the beakhead, as Pevsner does of Bishop Wilton, assumes a link of either formal derivation or meaning between the two motifs, although that is debatable.

The fluted motif on the outer arch order on the N doorway at Kilnwick-on-the-Wolds has comparisons at Bishop Wilton on the chancel arch and at Fangfoss on the doorway, where a variety of patterns are used, though more subtly than in the present example.

The font is 'Transitional' in date, i.e. last quarter of the 12thc, according to Morris; Pevsner and Neave (1995, 578) say "Late 12C. Circular basin with cable moulding on C19 shaft." The distinctive sawtooth motif - a sloping angular pattern referred to here as dentation - was used at Skipwith on a late 12thC arcade, also recorded by this Corpus. It appears again on, for example, the S doorway at Fangfoss where it is set point-to-point on both faces of the label, and on string-courses. Planar, platform-like features, as on the outer arch order of the Kilnwick doorway, were used at Fangfoss with many different patterns, including radial ridges and scallops, and with more uniform designs at Bishop Wilton. The font at Kilnwick is likely to be contemporary with the N doorway, mid- to late-12th-century in date.