Statistics for occurrence #1 of “Potomac River” in page 132 of Fitzhugh Lee, General Lee:

...ch closer to Richmond. Johnston and Beauregard after the battle of Manassas continued to occupy that section, extending their outposts, however, closer to Washington, while partially blockading the Potomac River by some
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Max. Freq. Min. Freq.
Entity Corpus Doc Corpus Doc  
Potomac River (United States) 286 0 0 0 0 user votes
Potomac River (Maryland, United States) 2 0 0 0 0 user votes
Potomac River (Maryland, United States) 2 0 0 0 0 user votes

† This entity has been selected by the automated classifier as the most likely match in this context. It may or may not be the correct match.