Statistics for occurrence #1 of “Illinois” in chapter 5 of George Bancroft, History of the United States from the Discovery of the American Continent, Vol. 3, 15th edition.:

...protected the French commercial establishment in their village. Such was the origin of the city of Natchez. In the Mississippi valley, it takes rank, in point of age, of every settlement south of Illinois . The monopoly of Crozat was terminated by its surrender. The mines, and commerce, and boundless extent, of Louisiana were now invoked to relieve the burden and renew the credit of the metropoli...
Max. Freq. Min. Freq.
Entity Corpus Doc Corpus Doc  
Illinois (Illinois, United States) 6,200 72 0 0 0 user votes
Illinois (New Mexico, United States) 4 0 0 0 0 user votes
Illinois (Oregon, United States) 2 0 0 0 0 user votes
Illinois (Colorado, United States) 0 0 0 0 0 user votes
Illinois (Illinois, United States) 0 0 0 0 0 user votes
Illinois (New Mexico, United States) 0 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.