The museum includes information and over 2 million artifacts associated with archaeology (e.g., Maiden Castle), geology (e.g., the Jurassic Coast), history, local writers (e.g. Thomas Hardy) and natural science.

[4] In 2016, the museum unveiled plans for a £13 million extension which would include a learning centre, cafe, library and shop, allowing the Dorset Natural History and Archaeological Society's full collection to hold together in one building.

[10] The Ancient Dorset Gallery was opened by Julian Richards in November 2015 and includes Viking historical artefacts from a nearby burial site.

Other artefacts include pre-historic flint hand axes, a Roman glass bowl and an Iron Age bronze mirror.

[12] In July 2016, the museum opened a gallery dedicated to the work of William Barnes, telling the story of his humble roots to his legacy in poetry, novels and music.

[17][16] No answer was given to one attendee’s question that: “Given that she [a British Museum curator] boasted the fact that the replicas they made were indistinguishable from the originals, surely it would make more sense to send the replica around the world and keep the original safe in Dorset?”[18] As of 2021[update], it was not clear whether the complete mosaic[19][20] or only a part of it would be displayed in the Dorset Museum.

[21] In July 2022 the Blackmore Vale newspaper reported that "discussions are at an advanced stage with a view to bringing the important Roman artefact to the Dorset County Museum in Dorchester or another site.

The building is two storeys high with a slate roof, it has two stringcourses on the gently sloped walls, with hood moulds over the windows and a crenellated parapet.

[23] To the rear of the building, the museum also owns John White's rectory, where he resided whilst obtaining charters for the colonisation of Massachusetts.