In 1958, and again between 1987 and 1994, the site was subject to major archaeological excavations, which uncovered information about prehistoric and medieval activity at Pennant Melangell, including evidence of Bronze Age burials.

The interior of the church holds historically valuable objects including a 15th-century rood screen depicting Melangell's legend, two 14th-century effigies, paintings, and liturgical fittings.

Remains of structures including sheepfolds, enclosures, shelters, huts, and peat-drying platforms suggest that the land was used for summer grazing and peat-cutting.

[15] Archaeological evidence of cremation pyres suggests that there was a burial mound at Pennant in the Bronze Age, possibly under the church itself.

[16] According to her hagiography Historia Divae Monacellae, Melangell sought refuge at Pennant after fleeing an arranged marriage in her native Ireland.

Brochwel granted her the land with perpetual sanctuary rights for anyone fleeing to Pennant, and Melangell went on to found a community of nuns.

[21] According to the historian Kathryn Hurlock, the shrine was erected around 1160–1170 to house Melangell's translated remains, and the 12th-century apse enclosed her original grave.

[29] An aisle on the south side of the chancel may have been added to aid pilgrims' access to the shrine in the late medieval period.

[32] The religious reforms under Henry VIII, Edward VI, and Elizabeth I, which suppressed pilgrimage and saints' cults, brought major changes to the fabric of the church; the shrine was probably dismantled at this time and the grave chapel blocked off.

[34] Significant repairs and renovations were undertaken throughout the 18th century, including blocking up doors and windows, building a new porch, replacing walls, and possibly dismantling the loft of the rood screen.

Despite the demolition of the original apse and removal of Melangell's shrine and relics, the tradition surrounding her persisted, and she continued to be associated with the cell-y-bedd.

At the same time, Paul Davies, the parish priest of Meifod, bought a cottage near the church with his wife following her recovery from cancer.

Davies was licensed by the diocese to look after the church on a voluntary basis; under his care, a cancer help centre was started out of their cottage and a complete restoration was undertaken.

A service of thanksgiving, attended by the Archbishop of Wales Alwyn Rice Jones, was held on 27 May 1992 in commemoration of the restoration work.

Evelyn Davies was succeeded in the position, which oversees the ministries of the church, by Linda Mary Edwards in 2003 and Lynette Norman in 2011.

In a 2004 survey of pilgrimage to the site, common motivations for visiting included spiritual, historical, archaeological, and architectural interest.

The isolated, scenic location of the church was also a factor in attracting visitors, and played a role in pilgrims' perception of the site as sacred.

Several small pits filled with loam were discovered with high concentrations of charcoal and bone fragments, indicating cremation burial.

[51] Pieces of Bronze Age pottery were discovered underneath the west end of the church; nine sherds were recovered in total.

When contaminated[e] topsoil was removed from the east of the churchyard in 1987, several previously unknown graves laid with cobblestone were discovered, dating from the mid-18th to the mid-19th centuries.

The fragments were noted by Thomas Pennant and John Parker, but were thought to be remnants of an earlier church until Worthington George Smith identified them as a former shrine in 1894.

[24] In 1958, the shrine was reconstructed in the cell-y-bedd by the architect R. B. Heaton, based on a study by Ralegh Radford and incorporating an altar and reliquary.

The building is constructed of waterworn pebbles, larger slabs of sedimentary rock, and blocks of shale; different portions of the church date to varying periods, from the 12th to the 20th centuries.

[64] Most of the structure was built in 1751 to replace the medieval apse and consisted of a small, irregular rectangular room with a single window and a fireplace.

[73] Above the altar was a 1791 reredos featuring the Ten Commandments, the Apostles' Creed, and the Lord's Prayer, all in Welsh and decorated with cherubs; this painting was later conserved and moved to the tympanum.

[74] The carved wooden rood screen dates to the late 15th century, and contains the earliest surviving depiction of Melangell and the hare.

The carvings on the rood screen depict Prince Brochwel on horseback, a huntsman, Melangell, the hare, and two hunting dogs within a foliated running border.

[79] The male effigy depicts a young man with a sword and shield, lying with his head resting on cushions, and an animal (possibly a wolf) beneath his feet.

[79] Thomas Jones, an 18th-century vicar of Pennant Melangell known for his eccentricity, supposedly attacked the effigy's legs with a stone during an outburst, causing lasting damage.

The figure wears a long gown and a square headdress characteristic of the late 14th century, with a lion at her feet and two animals at either side.