Sudbury was part of the Nipissing riding until 1947, when the Sudbury riding was created. It initially included a large portion of the Sudbury District; in 1952, the boundaries were narrowed significantly to include only the city of Sudbury, the geographic township of McKim and the town of Copper Cliff. The rest of the original Sudbury riding was incorporated into the new riding of Nickel Belt.
In 1976, Sudbury's growth in population led the riding to shrink further. It now included only the northern half of the city; the city's southern half was incorporated into Nickel Belt.
In 2004, a decline in population led to this riding expanding geographically to include the former town of Walden, now part of the city of Greater Sudbury. The remainder of the city continues to be part of the Nickel Belt riding.
Sudbury electoral district consists of the part of the City of Greater Sudbury bounded on the west and south by the Greater Sudbury city limits, and on the north and east by a line drawn from the western city limit of Greater Sudbury east along the northern limit of the former Town of Walden, north, east and south along the limits of the former City of Sudbury, west along Highway 69 and Regent Street, south along Long Lake Road, west along the northern boundary of the Township of Broder, southwest along Kelly Lake, and south along the eastern limit of the former Town of Walden to the southern city limit of Greater Sudbury.
Sudbury electoral district was created in 1947 from parts of Nickel Belt and Nipissingridings. It consisted initially of the city of Sudbury and a part of the territorial district of Sudbury.
In 1952, it was redefined to consist of the city of Sudbury, the township of McKim, and the town of Copper Cliff. In 1966, the Township of McKim was removed from the riding.
In 1976, it was redefined as the northern part of the City of Sudbury. In 1996, it was redefined as the part of the City of Sudbury north of a line drawn from east to west along Highway 69, south along Long Lake Road, and west along the north boundary of the geographic Township of Broder.
In 2003, it was given its current boundaries as described above.