John W. Donnellan | |
|---|---|
 | |
| 1st Treasurer of the Wyoming Territory | |
| In office December 21, 1869 – October 26, 1872 | |
| Succeeded by | Stephen W. Downey |
| Personal details | |
| Born | June 8, 1841 County Clare, United Kingdom of Great Britain and Ireland |
| Died | July 26, 1917 (aged 76) Sacramento, California, U.S. |
| Resting place | Sacramento Historic City Cemetery |
| Political party | Democratic |
| Spouse | Marion J. McNasser |
| Children | 3 |
| Military service | |
| Allegiance |  United States of America |
| Branch/service | Union Army |
| Years of service | 1861-1865 |
| Rank | Lieutenant colonel |
| Unit | 83rd Ohio Infantry 27th Colored Infantry Regiment |
| Battles/wars | American Civil War |
John W. Donnellan (June 8, 1841 – July 26, 1917) was an American politician who served as the 1st Treasurer of the Wyoming Territory as a Democrat.