| Carey, Mathew. Delaware. Engraved by A. Doolittle, 1796 | Complete |
| Carey, Mathew. Georgia. Philadelphia: Lang and Ustick, 1796 | Complete |
| Carey, Mathew. Province of Maine. Philadelphia: Lang and Ustick, 1796 | Complete |
| Causes of the failure of the expedition against the Indians in 1791, under the command of Major General St. Clair, 1792 | Complete |
| Census of Illinois Territory, 1818 | Complete |
| Census of the State of Illinois, 1820 | Complete |
| Chapman Publishing Company. Portrait and Biographical Album of St. Clair County, Illinois Containing Biographical Sketches of Prominent ... Citizens, Together with Biographies and Portraits of All the Presidents of the United States. Chicago, 1892 | Complete |
| Chapman, Leorah May Copeland. A History of Johnson County, Illinois. Herrin, Ill.,: Press of the Herrin news, 1925 | Complete |
| Clermont County Proclamation, 1800 | Complete |
| Combined history of Edwards, Lawrence and Wabash counties, Illinois. With illustrations ... and biographical sketches of some of their prominent men and pioneers. Philadelphia, J. L. McDonough & co., 1883 | Complete |
| Combined history of Randolph, Monroe and Perry counties, Illinois : with illustrations descriptive of their scenery and biographical sketches of some of their prominent men and pioneers. Philadelphia: J.L. McDonough & Co., 1883 | Complete |
| Connecticut (state) | References Only |
| Connecticut (state) -- Fairfield (county) | References Only |
| Connecticut (state) -- Hartford (county) | References Only |
| Connecticut (state) -- Litchfield (county) | References Only |
| Connecticut (state) -- Middlesex (county) | References Only |
| Connecticut (state) -- New Haven (county) | References Only |
| Connecticut (state) -- New London (county) | References Only |
| Connecticut (state) -- Tolland (county) | References Only |
| Connecticut (state) -- Windham (county) | References Only |
| Connecticut Cession of Western Land Claims, 1786 | Complete |
| Constitution of the State of Illinois, 1818 | Complete |
| Constitution of the State of Illinois, 1848 | Complete |
| Constitution of the State of Illinois, 1870 | Complete |
| Constitution of the State of Illinois, 1970 | Complete |
| Constitution of the State of Indiana, 1816 | Complete |
| Constitution of the State of Indiana, 1851 | Complete |
| Contract Between the American Inhabitants and Tardiveau, 1787 | Complete |
| Contract Between the French Inhabitants and Tardiveau, 1787 | Complete |
| Court of Inquiry on General Harmar, 1791 | Complete |
| Cox, John E. Thomas Price (a Pioneer in Posey County, Indiana) and His Descendants; a History and Genealogy. Owensville, Ind.,: Printed in the Messenger office, 1926 | Complete |
| Cranmer, Gibson L., et. al. History of the Upper Ohio Valley with Family History and Biographical Sketches. Volume I. Madison, Wis.,: Brant &Fuller, 1890 | Complete |
| Cranmer, Gibson L., et. al. History of the Upper Ohio Valley with Family History and Biographical Sketches. Volume II. Madison, Wis.,: Brant &Fuller, 1890 | Complete |
| Crawford, H. Marjorie. Crawfords of Adams County, Ohio. Poughkeepsie, N.Y.: s.n., 1943 | Complete |
| Creation of Clark County, 1801 | Complete |
