This event documents the air photo mapping element of the Magnesian Limestone in South and West Yorkshire: Archaeological Mapping and Assessment Project and forms part of the National Mapping Programme (NMP).The Magnesian Limestone in South and West Yorkshire Project is funded by the Aggregates Levy Sustainability Fund (ALSF) (as disbursed by English Heritage) and operated by Archaeological Services WYAS (ASWYAS), Nepshaw Lane South, Morley, Leeds LS 27 0QP. As a whole the Magnesian Limestone in South and West Yorkshire Project is a multi-disciplinary project that aims to integrate the results of past excavation, geophysical survey and field walking with the information from high quality air photo mapping. Its overarching aim is to redefine baseline knowledge (of the ancient landscapes of the Magnesian Limestone) and so enable future aggregate extraction to be mitigated more appropriately within a considered archaeological research framework (Roberts and Deegan 2005, 2). The air photo mapping element is being carried out to EH's standard National Mapping Programme (NMP) specification by a small team of interpreters contracted by ASWYAS and based with EH's Aerial Survey and Investigation team at Tanner Row, York. Work on this element began on 3rd March 2005 and was completed in February 2006. The air photo mapping project covers 23 whole OS 1:10,000 scale quarter sheets, a total area of 575 km2. It lies almost entirely within the county of South Yorkshire, with partial overlaps into North Yorkshire, West Yorkshire and Nottinghamshire. The air photo mapping project will interpret and transcribe, at a nominal scale of 1:10,000, all upstanding and levelled archaeological features, dating from prehistory to the twentieth century, that are visible on air photographs. Scanned air photographs (or overlays) will be rectified with AERIAL 5.24 using control derived from Ordnance Survey 1:2500 Landline data. Archaeological features will be transcribed in AutoCAD Map 2004 in the standard NMP layer system. The air photo interpreters will update and enhance existing National Monument Records in the live NMR AMIE database and create new records where necessary.The principal output from the air photo mapping element of the Magnesian Limestone in South and West Yorkshire Project will be digital maps and records. The parent project, which covers a larger geographic area, will integrate these and the results from the previous Lower Wharfedale and Vale of York NMP projects with data from other investigations to produce a synthesis and inter-county overview of the rural archaeological landscapes of the Magnesian Limestone belt. The wider project is due for completion in December 2006.