A by-election was held for the New South Wales Legislative Assembly electorate of Mudgee on 29 June 1886 because of the resignation of John Robertson attributed to ill-health, financial difficulties and loss of the premiership.[1]
| Date | Event | |
|---|---|---|
| 19 June 1886 | Writ of election issued by the Speaker of the Legislative Assembly.[2] | |
| 29 June 1886 | Nominations | |
| 2 July 1886 | Polling day | |
| 8 July 1886 | Return of writ |