The seat has been around since federation and for almost 100 years it has been a Country/National Party stronghold, with independent MP Tony Windsor's 12-year reign the only interruption.

The 66,000-square-kilometre region stretches from the Queensland border in the north, down to the edge of the Hunter Valley in the south.

Of the roughly 154,000 people living in the electorate just over 110,600 are enrolled to vote.

In 2017, a by-election was triggered by the revelation incumbent Nationals MP Barnaby Joyce was a dual-citizen due to his father's New Zealand heritage.

He was ruled ineligible to stand, but retook the seat with more than more than 57,000 votes or almost 65 per cent of first preferences.

Of the 15 other candidates, Labor's David Ewings was the only one to reach double digits.

Just over 96,400 votes were cast, or 87 per cent of the population.

Close to one in 10 votes were informal.

This year, Mr Joyce is seeking to be re-elected for a third term and is facing competition from seven candidates.

Independent Adam Blakester has been running an intense grassroots campaign - he's based his policy platform off more than 4000 one-on-one conversations.

Armidale businessman Rob Taber and Uralla councillor Natasha Ledger are also running as independents.

University of New England lecturer Yvonne Langenberg is standing for the Labor Party, and domestic violence advocate Cindy Duncan is representing the Clive Palmer-backed United Australia Party.

Aberdeen farmer Tony Longeran, who stood for the Greens in the seat of Upper Hunter at the recent state election, will again stand for the party.

Julia Collins will run for the Christian Democrats.