Plat maps show the location of parcels within subdivisions.

Plat maps for the original plats of the City of Ann Arbor http://www2.a2gov.org/gisonline/Plats/plat-index.asp. To find a Plat, you will need the name of the subdivision, easily available by looking up the parcel on the Assessment and Property Tax Data section of the City of Ann Arbor Website. 

The Bentley Historical Library's list of landowner maps for the county provides a comprehensive list, 1856 to date.