Winstanley Hall is one of four closely related late 16th century houses in the neighbourhood of Wigan, the others being Bispham Hall of 1573, Birchley Hall of 1594 and Hacking Hall of 1607.
Winstanley Hall is of three storeys, the top half within the roof, and has always differed slightly from the others in the group in that the left-hand cross-wing also projects to the rear. Its exact date is not entirely clear; a much worn datestone of 1584 remains, but not in situ, and it seems most likely that the house was built immediately after the property was bought by James Bankes in 1596.
The first alteration took place during the 17th century and was the addition of a block against the flank of the right-hand cross-wing (the former service end). This retains its mullioned and mullion-and-transom windows on the small part of its external surface which is still exposed. In the mid-18th century a single-storey addition was built against the back of the hall and the, in 1780, a Mr Robinson, architect of Middleton, provided a design for comprehensively remodelling the house, although in event only a reduced version was executed. The rear block was raised to the full height of the house, a canted bay was added to the rear end of the left-hand cross-wing and the ground-floor windows to the front ends of both wings were replaced by large tripartite openings.
The most extensive alterations were carried out in 1811-19 by Lewis Wyatt. Externally, they were in a Jacobean style. The left-hand flank was converted into the entrance front and in its present form is is entirely Wyatt's work, a symmetrical composition with a projecting four-storey tower in the centre, preceded by a single-storey Tuscan porch. On the original front the entrance was replaced by a window, the remaining ground-floor windows were renewed and enlarged. The alterations were completed by a wing of 1843 running in front of this block.