John I. De Graff | |
|---|---|
 | |
| Mayor of Schenectady | |
| In office 1845–1846 | |
| In office 1842–1843 | |
| Member of the United States House of Representatives from New York | |
| In office March 4, 1837 – March 3, 1839 | |
| Preceded by | John Cramer |
| Succeeded by | Anson Brown |
| Constituency | 11th district |
| In office March 4, 1827 – March 3, 1829 | |
| Preceded by | William Dietz |
| Succeeded by | Peter I. Borst |
| Constituency | 12th district |
| Mayor of Schenectady | |
| In office 1836–1837 | |
| In office 1832–1835 | |
| Personal details | |
| Born | October 2, 1783 Schenectady, New York |
| Died | July 26, 1848 (aged 64) Schenectady, New York |
| Political party | Jacksonian Democratic |
| Education | Union College |
| Military service | |
| Allegiance |  New York |
| Branch/service | New York militia |
| Years of service | early 1800s |
| Rank | Ensign |
| Unit | Schenectady regiment |
John Isaac De Graff (October 2, 1783 – July 26, 1848) was an American businessman and politician who served two non-consecutive term as a U.S. Representative from New York 1827 to 1829, and again from 1837 to 1839.