A by-election was held for the New South Wales Legislative Assembly electorate of The Williams on 19 April 1866 because the seat of Frederick Manton was declared vacant due to insolvency.[1]
| Date | Event | |
|---|---|---|
| 22 January 1866 | Frederick Manton elected in the by-election. | |
| 29 March 1866 | Frederick Manton's seat declared vacant due to insolvency. | |
| Writ of election issued by the Speaker of the Legislative Assembly.[2] | ||
| 14 April 1866 | Nominations.[3] | |
| 19 April 1866 | Polling day | |
| 30 April 1866 | Return of writ |