Report on a heritage impact assessment and fluxgate gradiometer survey conducted to inform proposed residential development on land to the north of Main Street, Mareham le Fen. Several modern and post-medieval features were identified, including a moat in the northeast corner of the site visible on historic OS maps, and a modern pond and drainage ditch further west. A cluster of amorphous positive anomalies were encountered in the southwest corner of the site. These were interpreted as possible waste pits, dumps, or kilns related to a known 14th century tile kiln immediately to the south on the street frontage (see ELI31). A number of positive linear anomalies crossing the centre of the site were suggested to be geological in origin. The impact of development on the site was considered to be high for Medieval archaeology, and low or negligible for all other periods.