| John O'Neill | |
| State: | Ohio |
| District: | 13th |
| Term Start: | March 4, 1863 |
| Term End: | March 3, 1865 |
| Preceded: | Samuel T. Worcester |
| Succeeded: | Columbus Delano |
| State Senate2: | Ohio |
| District2: | 15th & 16th |
| Term Start2: | January 7, 1884 |
| Term End2: | January 1, 1888 |
| Alongside2: | Edwin Sinnett |
| Preceded2: | John D. Jones |
| Succeeded2: | Joseph G. Huffman Edwin Sinnett |
| Birth Date: | 17 December 1822 |
| Birth Place: | Philadelphia, Pennsylvania, U.S. |
| Death Place: | Zanesville, Ohio, U.S. |
| Resting Place: | St. Thomas Cemetery |
| Party: | Democratic |
| Alma Mater: | Mount St. Mary's University Georgetown University Law Center |
John O'Neill (December 17, 1822 - May 25, 1905) was an American lawyer and politician who served as a U.S. Representative from Ohio for one term from 1863 to 1865,
Born in Philadelphia, O'Neill attended the common schools at Frederick, Maryland, and Georgetown College, Washington, D.C. He was graduated from Mount St. Mary's College, Emmitsburg, Maryland, and from the law department of Georgetown College, Washington, D.C., in 1841. He was admitted to the bar in 1842. He moved to Zanesville, Ohio, in 1844 and commenced the practice of law.
He served as the prosecuting attorney of Muskingum County in 1845. He also held various county offices. He was United States Attorney for the Southern District of Ohio 1856-1858.[1]
O'Neill was elected as a Democrat to the Thirty-eighth Congress (March 4, 1863 - March 3, 1865). He resumed the practice of his profession.
He served as member of the Ohio Senate 1883-1885. He then practiced law until his death in Zanesville, Ohio, on May 25, 1905. He was interred in St. Thomas' Cemetery.