America's Historical Newspapers (1690 to 1922) provides access to scanned images from newspapers from all 50 U.S. states.
Newspapers.com is a full-text database of newspapers from the U.S. and
Chronicling America is a joint project of the Library of Congress and the National Endowment for the Humanities, providing access to digitized newspapers from the U.S. and Puerto Rico. Coverage is 1777 to 1963 but varies by title.
17th and 18th Century Burney Collection Newspapers provide access to the British Library's collection of newspapers donated by the Reverend Charles Burney.
17th and 16th Century Nichols Newspaper Collection is a database of the Bodleian Library's collection of 17th and 18th century papers gathered by John Nichols, former Master of the Stationers’ Company.
Caribbean Newspapers, 1718-1876 provides full-text access to over 60 newspapers from over 20 islands.