The Sheffield City Region is an area of England centred on Sheffield a population of 1,819,500 covering an area of 3,517.84 km2 in 2004. It was one of eight city regions defined in the 2004 document Moving Forward: The Northern Way, as a collaboration between the three northern regional development agencies. It covers the entirety of the metropolitan county of South Yorkshire, and also adding four districts from north Derbyshire, and one district from northern Nottinghamshire. The Sheffield City Region Enterprise Zone promotes development in a number of sites across the region.