This report presents the results of a heritage assessment that was carried out by South West Archaeology Ltd. (SWARCH) for a residential development at The Barns at Moigns Down Farm, Owermoigne, Dorchester, Dorset. The cartographic, documentary, and building evidence at the site would suggest that Moigns Down Farm has been occupied from at least the later Medieval period onwards, whilst early fabric that remains within the northern elevation of the former threshing barn (B1) is of possible earlier origin. The site is a multi-phase complex with an involved narrative that is currently focused on the former threshing barn (B1), with the farmhouse having been demolished during the 1970s. Further evidence may be found within the Dorset County Records that could clarify the date of establishment of the farmstead and identify the earlier phases of ownership that are linked either to the several Medieval manors within the area or to an ecclesiastical estate known as an area of extra parochial place. The archaeological evidence, including Scheduled Monuments of earlier Prehistoric activity within the high downs that surround the site, the record of a mill in the Domesday Survey within the wider valley, at least one deserted Medieval village, an ancient battle site, and early coin find spots, provide the context for the farmstead of a historically rich and diverse landscape that is quite at odds with its isolated character of today. The site in recent times has been associated with the neighbouring farmstead of Watercombe, however it also has earlier historic links with the estate at Warmwell and the manor at Poxwell. The lost farmhouse and the deserted cottages are indicative of a more substantial farming hamlet that survived well into the 20th century. The ruined stone farm buildings and the yards include some areas of archaeological interest and architectural value, such as the stone pillars. The northern elevation of the former threshing barn (B1) is significant as it includes the earliest datable fabric on the site, whilst vernacular features that include the slit vents in the elevations and the high pitched roofline would suggest that the former threshing barn (B1) dates to either the 16th century or the 17th century. The principle for the development of the former threshing barn (B1) into a dwelling is fully supported, however there is an acknowledgement that its conversion would be permanent and irreversible. That being said, it is also felt that conversion is the only feasible solution to the potential loss of this important local undesignated heritage asset without further intervention. The remaining ruined buildings and upstanding walls are important to the setting and the context that they create for the former threshing barn (B1) and the narrative that they provide to the farmstead, however they contain far more flexibility for change. That being said, any development of the farmstead should be sensitively considered at the design stage to avoid unnecessary historic pastiche and it is expected that any conversion scheme would consult with the local conservation officer and be developed with the aid of heritage professionals to ensure the suitability and the sustainability of the farmstead for future generations.