An archaeological excavation was undertaken at Colne Fen, Earith (NGR TL 3840 7730). The fieldwork was commissioned prior to the extension of the current quarry workings and follows previous investigations within the wider landscape. 0.52ha and c. 50m of trial-trenching were excavated targeting specific cropmarks and areas archaeological features investigated during an earlier evaluation. With the site, north of Rhee Lake and abutting the Langdale Hale complex, the excavation provided evidence for activity dating back to the Mesolithic, including a Bronze Age field boundary and a substantial Iron Age enclosure and roundhouse and the continuation of Romano-British activity from Langdale Hale towards Rhee Lakeside. Evidence for the Rhee Lake palaeochannel was present in the form of a large swathe of alluvial clay, almost entirely devoid of archaeological features.