[1] The former St Columba's Convent was built in 1913 for the Sisters of Mercy from a design by local architect George Bernard Roskell, to provide accommodation for the nuns and the boarding students in their care.

The Sisters of Mercy occupied the convent until 1990, after which it was purchased by the Dalby parish and used as a student hostel, before being leased as a youth and community centre.

Due to an error in flood levels, Captain Samuel Augustus Perry, the Deputy Surveyor General of New South Wales resurveyed the township in 1853, naming it Dalby after a location on the Isle of Man.

A small group of Sisters of Mercy arrived in Dalby on 8 August the following year, from the Toowoomba convent established in 1873; and this new Plough Inn became the order's eleventh school in Queensland known as St Columba's.

[1] Dalby's regional prosperity was spurred by a number of legislative processes aimed at rural development in the late 19th and early 20th centuries, including the creation of smaller land holdings and the construction of new railways.

[1] The growth of the area and the general expansion of the network of boarding schools led to the planning of a new, purpose-built Catholic convent for Dalby.

Michael Kelly departed Dalby the following week to take up the position of Clerk of Works for St Brigid's Church at Red Hill, Brisbane.

Entry to the property was through ornamental iron gates composed of crosses with the name St Columba's Convent emblazoned on them in brass.

A gravelled path led to the central main entrance, which had a simple gabled portico again lettered with the name of St Columba's.

[1] The chief towns of the Darling Downs - namely Toowoomba, Warwick and Stanthorpe - became, along with Dalby, centres of education with the establishment of a number of day and boarding schools by different Christian denominations.

Around the time of the construction of the convent at Dalby, other Christian boarding schools were established in Toowoomba and Warwick but were not overseen by an order of nuns or brothers.

A number of smaller convents and schools were established on the Downs after 1913, including at Allora, Clifton, Crows Nest, Oakey, Miles, Chinchilla and Yarraman.

In 1963 St Mary's Christian Brothers College was established in Nicholson Street, near the Dalby Airport, to educate boys from grades 5 to 10.

In October 1990, the Sisters of Mercy departed Dalby, as part of the trend towards co-educational colleges staffed by lay teachers and managed through Diocesan Education Offices.

In 1991, the Dalby Parish Finance Committee purchased the convent from the Sisters, upgraded its facilities and established a non-denominational rural student hostel, known as St Joseph's, servicing the regional community.

St Columba's school to the rear of the convent was extensively fire damaged in 1998 and the decision made to begin a process of relocation to Nicholson Street.

In May 2006 the Myall Youth and Community Network Centre (MYCNC) moved into the former convent, however in mid-2010 it was awaiting completion of purpose-built facilities in Diplock Park opposite Dalby High School.

[1] The former St Columba's Convent occupies a corner block in the south-western part of Dalby, 80 kilometres (50 mi) north-west of Toowoomba on the Darling Downs.

Opposite it along Cunningham Street are the Dalby Ambulance Station and several residences; whilst further to the north-east are St Joseph's Catholic Church and the adjacent Presbytery (not original).

[1] The Cunningham Street facade is largely symmetrical, with a central portico formed in timber and verandahs running behind it between the brick walls of the two main gabled wings.

A multitude of window types feature, including original timber-framed double-hung sashes, four-light timber casements, and aluminium-framed sliders.

The ground floor layout of the former St Columba's Convent remains substantially intact, with only one interior wall removed (in the kitchen).

The stained glass of the sanctuary features flowers and symbols such as alpha and omega, whilst all other windows contain leadlighting in various shades of green.

[1] The south-western wing contains two large rooms at the northern end, with original bi-fold timber doors made of eight panels, approximately 2.7 metres (8 ft 10 in) high, dividing the former boarder's study from the refectory.

The brick enclosed staircase in the north-western corner of this wing has a simple, painted timber balustrade, carpeted stairs and pressed metal on the underside of the upper landing.

Next to the main door is a large brass plaque, commemorating the blessing and reopening of the building as St Joseph's Parish Hostel in 1991.

St Columba's Convent, a substantial brick and timber building constructed and opened in 1913 almost debt-free because of the donations made by parishioners, strikingly demonstrates the prosperity generated through pastoralism and agriculture on the Darling Downs, one of the most productive rural areas in Queensland.

[1] St Columba's, designed by local architect George Bernard Roskell and constructed for the Sisters of Mercy, demonstrates the spread of the Catholic Church in regional Queensland, and in particular the significant contribution played by this order of nuns in the spiritual and educational development of the state through its establishment of convents, schools and boarding accommodation.

In terms of layout and interior finishes, the former convent is also highly intact and therefore strongly illustrative of this type of cultural place: including ground floor chapel and sacristy, stained glass and leadlight windows, decorative timberwork, refectory and reception rooms and first floor nun's cells and boarders' dormitory with a coved, pressed metal ceiling.

St Columba's Convent is an elegant architectural composition with great aesthetic merit, with its triple-gabled front facade, walls of face brick with cement rendered bands, and a perimeter of timber verandahs.