Ms Gillard, joined by partner Tim Mathieson, will spend five days in the country. It is her first to the US since becoming prime minister.
Besides important talks, she'll walk the floor of the New York Stock Exchange, while also becoming just the fourth Australian to address a joint sitting of Congress.
That is scheduled for the early hours of Thursday morning (AEDT).
US ambassador Jeff Bleich said the invitation for her to speak showed just how important Australia was to the US.
"Most people agree the Asia-Pacific has become the centre of gravity for the world's economies and demographics," he said.
"It's the largest centre for population growth and GDP - and that raises Australia's prominence.
"When everything is fluid and dynamic, whether in international relations or personal life, the thing you look for first is who your true friends are."
He expects Ms Gillard will be pressed about Australia's push to implement a carbon tax, given America's own debate about how best to tackle climate change.
Ms Gillard is due back in Australia next Saturday.
