Chronicling America by the Library of Congress includes the ability to search digitized newspapers for free from 1770-1963. There currently are 65 Maryland newspapers digitally available. On this site you also can search the U.S. Newspaper Directory, 1690-Present, for information on newspapers whether or not they have been digitized. There currently are 1,789 titles listed for Maryland.

The Enoch Pratt Library offers searching of some historical Maryland newspapers (and current papers) online with your library card. This includes the "Baltimore Afro-American" and the "Baltimore Sun." Maryland residents can get a free library eCard to access these databases.

A good general page on the FamilySearch Wiki on researching newspapers.

GenealogyBank features a wealth of material, particularly modern obituaries and historical newspapers, as well as books, pamphlets, military records, government documents and more. There are over 15,000 newspapers available, including 245 Maryland newspapers starting as early as 1728.

Digitized newspapers from the collection of the Edward H. Nabb Research Center for Delmarva History at Salisbury University, dating from 1745 through 1922.

The Library of Congress has created libguides by topic on specific areas of newspaper research. You can search their collection (in-person) or there are links where newspapers might be accessible online.

A consolidated list of links to online Maryland historical newspapers at various repositories. Some include: Google News Archive; the Historical Society of Cecil County; Queen Anne's County Library; St. Mary's County Library; Worcester County Library; Somerset County Library; and Washington County Free Library.

The Maryland State Archives Special Collections newspaper database includes what they have digitized and made available online, as well as information about newspapers not in their collection. It lists institutions that may have original or microfilm newspaper holdings.

NewspaperArchive has content from over 16,000 newspapers and over 3,400 cities from all over the world. Over 20 Maryland communities are included. Members of the National Genealogical Society can access NewspaperArchive.com at no additional cost (https://www.ngsgenealogy.org/newspaperarchive/).

This site has over 920 million pages of newspapers from the 1700s–2000s. Newspapers from over 30 Maryland communities are represented. Ancestry All Access members have access to the basic version of this database as part of their membership.