Family history website Findmypast (findmypast.co.uk) has added an exclusive collection of 25 million electoral registers from Manchester, dating from 1820–1940.
Electoral registers are lists of the names and addresses of eligible voters in a particular district. They are a good resource for seeing where your ancestors lived, particularly in years when census records are not available, although note that they do not include additional information such as the person's age or profession.
The collection can also be searched by