'Remain' campaigners in Waveney say early indications show a swing in support towards their campaign - but Vote Leave say they still expect to win by a big margin in the district.
Votes are currently being verified for the Waveney district at Lowestoft's Waterlane Leisure Centre, with counting agents for both sides eagerly looking at ballot papers to try and see which side is coming out on top.
The result is expected to be declared at around 3am to 4am.
Simon Tobin, a UK Independence Party (UKIP) parliamentary candidate at the last general election and co-ordinator for Vote Leave in Waveney, said: 'I may be wrong, but I have to go by my gut feeling and I think we will win with 65 per cent of the vote in Waveney - but then there is the country.'
He added that the Vote Leave campaign's estimations were for a 65 per cent turnout in Waveney.
But Mark Bee, the Waveney agent for Stronger In, is predicting a higher turnout of about 75 per cent, based on remain campaigners activity at polling stations throughout the day.
He cited a polling station in Mettingham, near Bungay, which looked as though it had recorded a turnout of around 75 per cent - even though it usually has relatively low turnouts even in a general election.
Mr Bee added: 'I came here quite pessimistic that the leave campaign would win by a huge margin in Waveney.
'While I'm not confident remain will win in Waveney, we're beginning to now see that is actually narrowing. It may be a closer margin than people think.
'If that's happening in Waveney, that gives a clue as to the national situation.'
Tod Sullivan, who is also working on the remain campaign, said: 'I'd be amazed if here wasn't an out vote - it's whether we can keep that margin down enough in a close national vote.
'It looks like the turnourt has been really high in some of these rural communities.'
James Reeder, chairman of the Lowestoft and Waveney Chamber of Commerce, has remained neutral on the EU issue throughout the referendum campaign.
He said the debate had been 'passionate' and 'hasn't shown politics in the best light'.
He added: 'I just sincerely hope that whatever the result, that politics will move on.
'We have seen leaders of different parties on the same stage actually agreeing on something. It's great to think this could actually make a different kind of politics.'
Sonia Barker, leader of the Labour opposition group on Waveney District Council - who has been campaigning for remain - spent about six hours trying to get voters to the polls.
She said: 'This is a historic occasion. It's not like a general election or district election - this is something far more significant with long-lasting consequences into the future.'
Keep an eye on our website for more updates.
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