Greenfield is a village in the civil parish of Saddleworth in the Metropolitan Borough of Oldham, in Greater Manchester, England. It is 4 miles (6.4 km) east of Oldham and 13 miles (21 km) north-east of Manchester. It is located in a broad rural area at the southern edge of the South Pennines; Dovestone Reservoir, Chew Reservoir and Greenfield Reservoir lie to the east of the village in the Peak District National Park.

The South Pennines is a region of moorland and hill country in northern England lying towards the southern end of the Pennines. In the west it includes the Rossendale Valley and the West Pennine Moors. It is bounded by the Greater Manchester conurbation in the west and the Bowland Fells and Yorkshire Dales to the north. To the east it is fringed by the towns of West Yorkshire whilst to the south it is bounded by the Peak District. The rural South Pennine Moors constitutes both a Site of Special Scientific Interest and Special Area of Conservation.