A by-election was held for the New South Wales Legislative Assembly electorate of Gwydir on 29 June and 20 July 1865 as a result of the Committee on Elections and Qualifications declaring that the seat of Thomas Dangar was vacant because he had an office of profit under the Crown.
Dangar had been appointed the returning officer but was persuaded to stand for the seat, resulting in a delay of a month before the poll could be held.
[2] Dangar had a contract with the Government to carry the mail on the Barwon and Namoi rivers and this was held to be an office of profit and thus disqualified him from being a member of the Legislative Assembly.
Polling did not occur at the late added polling places until 20 July.
[8] It was a comfortable victory for Dangar, with his margin over Single increasing from 53 votes to 81 votes.