Directories of heads of households have been published for major cities in Maryland. For example, the Family History Library has the following Baltimore directories:
|1752, 1796-1860||FHL fiche 6043563-601|
|1863-1930||FHL films 1376528-56 & 1605845-71|
|1914||FHL film 1697549 item 1|
|1940, 1956||FHL book Q 975.271/B1 E4p|
The Enoch Pratt Free Library at http://www.prattlibrary.org/, the Maryland Historical Society at http://www.mdhs.org/, and the Maryland State Archives http://www.msa.md.gov/ have large collections of Maryland city directories. Local public libraries and county and city historical and genealogical societies are another good source of city directories, especially for small towns and cities.
Find directories in the Locality Search of the Family History Library Catalog under MARYLAND, [COUNTY], [TOWN] - DIRECTORIES.