Supporters of Democrat Kamala Harris hold on to hope, while some Trump backers insist only a conspiracy can stop the Republican former president returning to power.
As the first polls closed on the US east coast, the crowd started to swell inside one Sydney watering hole in the late morning.
Maggie Donahue was an earlier arrival and scored a prime spot near a screen tuned to CNN.
She came to watch the election coverage "with other Americans who are equally as concerned as I am about it".
"I am very cautiously believing, hoping, that Kamala will win by a narrow margin," she told AAP.
Ms Donahue worked for the US government over six years spanning the Trump and Biden administrations.
"I was in a federal government building the day of January 6, 2021," she said, referring to the date a mob of Trump supporters stormed the US Capitol.
Quietly confident Democrat supporter Amy Saha says the party feels united with a sense of momentum. (Bianca De Marchi/AAP PHOTOS)
Amy Saha, a committee member of Democrats Abroad Australia that is also hosting a watch party in Canberra, said she was quietly "but absolutely optimistic".
Ms Saha wore a star-spangled top hat and attendees could take photos with a cardboard cut-out of Ms Harris at the Sydney event.
The pub served American-brand beers and food including bagels and Buffalo wings, while the steak carried a side of "Freedom fries".
Sharing a bucket of Coors in the back of the Sydney pub, Ben, who declined to give his last name, said the beers were "alright" but not the main point of attending.
"We're coming here to support our president ... it's a Trump victory, unless they rig it of course," he said.
Sitting across the table, Dean Thorby said the Republican candidate's vacillation on abortion might cost him votes from women, but he still expected a Trump victory.
"Just because he's way more populist, she's way more of a drone," he said.
"You just have to look at the economy over the past four years and how everything has gone to s***," Ben interjected.
Venues are buzzing with US election watch parties as Americans and Australians ponder the outcome. (James Ross/AAP PHOTOS)
In Melbourne, former federal Liberal MP Katie Allen, Swinburne University vice-chancellor Pascale Quester and Victorian Labor MP Meng Heang Tak were among more than 50 people at an American Chamber of Commerce watch party.
The room at the Hawthorn Hotel was abuzz at 3pm as the election picture started to become clearer, with results breaking Trump's way.
Brisbane-based management consultant Emilia Gallo, who has worked for American companies in Asia, was firmly in the Harris camp despite donning a red-coloured blouse.
Ms Gallo admitted to nerves but told AAP she was hopeful of a turnaround, especially in the key swing state of Pennsylvania.
Melbourne resident Gavin, who has US business interests and did not wish to have his surname published, said Trump had his nose in front.
"I haven't seen Harris flip a state," the septuagenarian said with beer in hand.