1866 Illawarra colonial by-election

A by-election was held for the New South Wales Legislative Assembly electorate of Illawarra on 10 September 1866 following the resignation of Patrick Osborne.

Candidates
John Stewart had been the unsuccessful candidate at the 1860 election, receiving 46.% of the vote, and again at the 1864 election receiving 43.3% of the vote.

Result
Patrick Osborne resigned.