A by-election was held for the New South Wales Legislative Assembly electorate of The Lachlan on 10 January 1879 because James Watson was appointed Colonial Treasurer in the third Parkes ministry.
[1] Such ministerial by-elections were usually uncontested however on this occasion a poll was required in Canterbury (Sir Henry Parkes) and The Lachlan.
Both were comfortably re-elected.
The other 5 ministers were re-elected unopposed.
[2]