Abstract The Saltfleetby Gas Field is located onshore in East Lincolnshire at the western extent of the Humber Basin, midway between the Southern North Sea gas fields and the established Onshore Oilfields of Welton and Scampton North. Commercial discovery was in 1996, following the re-entry of a 1986 exploration well, confirming the pre-drill belief that the earlier drilling had been mis-appraised. Basic assumptions at the time of drilling the re-entry well suggested a possible 40 BCF gas-in-place in Early Westphalian sandstones. This assessment was based on only a single 2D seismic line, an association with gravity form, and the mud logging information from the earlier exploration well. Full delineation of the field extent following 3D seismic mapping and development drilling has indicated a gas-in-place of 114 BCF. Field development consent was granted in March 1999 and production commenced in December 1999. Initial field production exceeded 50 MMSCFD from four wells and to date (end July 2001) 24 BCF of gas has been produced. Ultimate gas recovery is expected to be 73 BCF proven plus probable reserves. A fifth horizontal well has been drilled in a deeper, Namurian, zone and a sixth well confirmed hydrocarbons in a southern promontory to complete the field development. An 8 km mixed phase export pipeline of 10" diameter exists to the Theddlethorpe processing plant, where gas and condensate is separated. Sharing of Pickerill compression facilities, located at Theddlethorpe were commissioned late in 2001.