- Calumet Press1
- Cam, Gilbert Arthur, 1906-1
- Campbell, Helen, 1839-19182
- Campbell, N. H1
- Campbell, Robert Dale1
- Campbell, William W., 1806-18811
- Canada. Department of Trade and Commerce1
- Cane, Melville Henry1
- Cantine & Leake1
- Cantor, Jacob A. 1854-19211
- Cantrell, S1
- Canty, Samuel1
- Capek, Thomas, 1861-19501
- Capek, Thomas, 1895-1
- Carey, Hugh L1
- Carey, Mathew, 1760-18391
- Carleton, George Washington, 1832-19011
- Carman, Harry J. 1884-19641
- Carnegie Trust Company1
- Caro, Robert A1
- Carpenter, W. H. 1813-18991
- Carpenter, William, 1797-18741
- Carr, Joseph Bradford, 1828-18951
- Carroll & Cook1
- Carroll, Charles, 1876-19361
- Carroll, G. Danielson1
- Carroll, George D1
- Carruthers, Ralph Herbert, 1903-1
- Carstensen, Georg, 1812-18571
- Carter, Robert, pub., New York1
- Carteret Book Club1
- Carver, William1
- Casa Italiana Educational Bureau1
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- Casey, T. L. 1831-18962
- Catella Jessurun, Jacob Spinoza, 1878-1
- Cathedral of St. John the Divine (New York, N.Y.)5
- Catholic Church. Archdiocese of New York (N.Y.)1
- Catlin, George S1
- Catlin, George, 1796-18721
- Catskill Chamber of Commerce1
- Cavaglieri, Giorgio, 1911-20071
- Center for Community Change1
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- Century Association (New York, N.Y.)3
- Chalmers, George, 1742-18251
- Chamber of Commerce (Queens, New York, N.Y.)1
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- Chamberlain, Alexander Francis, 1865-19141
- Chambers, Julius, 1850-19202
- Chandler, Charles Frederick, 1836-19252
- Chapin, Anna Alice, 1880-19201
- Chapin, Robert Coit, 1863-1
- Charity Organization Society of the City of New York1
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- Charles Scribner's Sons1
- Charter Revision Commission of the City of New York1