Stanford University: Journalism's Voyage West

The Growth of US Newspapers, 1690-2011 from Geoff McGhee on Vimeo.

This visualization plots over 140,000 newspapers published over three centuries in the United States. The data comes from the Library of Congress' "Chronicling America" project, which maintains a regularly updated directory of newspapers. 
Data visualization by the Rural West Initiative, Bill Lane Center for the American West, Stanford University
Credits: Dan Chang, Krissy Clark, Yuankai Ge, Geoff McGhee, Yinfeng Qin and Jason Wang

Link to the interactive Version.