[2][3][4][5][6][7][8] In the 1840 transcription and translation of the 12th-century Liber Landavensis... (Book of Llandaff), the sections on Llancillo state that the Early Middle Ages' king Meurig, who was patron for the Celtic Llandaff Cathedral, today in Cardiff, gave Llancillo to the cathedral and its bishop and saint Ufelwy, "for the redemption of his soul, to God, and the saints Dubricius and Teilo".

[5] In the first half of the 17th century was recorded an ironworking forge at Llancillo (grid reference SO37682528), using power from a tributary of the River Monnow at the south of the parish, including a leat, "weirs, ponds, dams, watercourses, houses and buildings".

Llancillo was in the Abbey Dore Union—poor relief and joint parish workhouse provision set up under the Poor Law Amendment Act 1834—and the petty sessional division and county court district of Hereford.

[11][12][13][14][15][16][17][18][19][20][21] The parish church of St Peter is described before 1870 as "a very old stone building" and "old, plain, and good", which included a nave, chancel, south porch, and a small bellcote at the west with one bell.

The parish living was consolidated with that of the vicarage of Rowl[e]ston, although during parts of the 1860s and 1870s being a perpetual curacy (an office supported by stipend rather than tithes or glebe).

Lord of the manor between the 1870s and the First World War was Edward Lucas-Scudamore ((1853–1917), later Colonel in the Hereford Regiment of Militia and JP, of the Castle Shane Estate, County Monaghan, and Cap House at Pontrilas.

Letters were delivered and received through the post town Abergavenny via Pandy, and from the 1880s the nearest money order and telegraph office was at Pontrilas.

[24] Adjacent Herefordshire parishes are Walterstone at the west, Longtown at the north-west, and Rowlestone at the north, with the Monmouthshire community of Grosmont at the south.

The parish is rural, of six farm complexes, fields, managed woodland and coppices, watercourses, ponds, and residential properties.

[25][26][27][28] Running east to west through the parish is part of the Golden Valley Pilgrim Way, which and passes St Peter's Church.

The Golden Valley Pilgrim Way is a 59 miles (95 km) circuitous footpath and road route through western Herefordshire, beginning and ending at Hereford Cathedral.

[31][32][33][34][35][36][37] Llancillo is represented in the UK parliament as part of the Hereford and South Herefordshire constituency, held by the Conservative Party since 2010 by Jesse Norman.

The nearest National Health Service doctor surgery is Golden Valley Practice at Ewyas Harold, 2 miles (3 km) north-west.

In the 17th century various further additions and alterations were added to the nave including windows and a door with arched lintel, and a gabled 17th-century stone south porch.

The chancel Norman east window is a round-headed single light lancet, similarly repeated in the north wall, its stained glass by William Pearce of Birmingham or Jones and Willis, dedicated to Joseph Larke Wheatley (1846-1932), who lived at Llancillo Hall and was a town clerk of Cardiff from 1879 to 1919.

The interior contains a part-octagonal pulpit of partly arabesque ornamented panelled oak at the north-east of the nave, dated by inscription to 1632, and 17th-century quire stalls which are a mixture of early to mid-17th-century pannelling and 18th-century end returns.

At the front of the south porch is a listed 19th-century churchyard preaching cross, set on a square three-step base dating to the 14th century.

On the motte are remains of rubble walling which might be evidence of a fortified tower, while it is surrounded partially by a ditch and outer rampart.

At 65 yards (60 m) north from Little Goytre is a listed timber framed and part weatherboarded barn (grid reference SO3567524465), dating probably to the 17th century and standing on a rubble stone course-work plinth, with a threshing floor in the centre of its three bays.

The north to south orientated tiled roof barn sits on a sandstone plinth and is part weatherboard cladded, and of four bays with a central threshing floor.