Far Blacklands Roman bloomery, at Cansiron Farm, Butcherfield Lane, Hartfield, East Sussex, is a Scheduled Ancient Monument, and has a high level of potential for further archaeological investigation, which will provide information relating to its history and use. As part of a High Level Stewardship agreement funded by Natural England, an archaeomagnetic survey was required in order to establish the full extent of the bloomery and to identify where alternative management regimes may be required to protect the entire archaeological site. The survey revealed an extensive ironworking site, covering most of the Scheduled Monument area, but also extending out into the edges of the surrounding fields. Within the central part of the site trackways and enclosures were identified, some of which contained evidence for ironworking activity, whilst along the old stream frontage there may be evidence for quays, suggesting links with the CLBR.