Prime Minister Scott Morrison - who the US president dubbed a "man of titanium" when they met at the White House - will join Mr Trump to open billionaire businessman Anthony Pratt's newest factory in Wapakoneta, Ohio.

The state is in Mr Trump's heartland and it's no accident Mr Pratt, who has cultivated a close relationship with the president, chose the location to build his biggest paper mill yet.

The visit will bring an end to the formal celebrations of the strong alliance.

Mr Morrison spent Friday and Saturday in Washington DC receiving the president and Melania Trump's hospitality and the magnificence of an official state visit.

"It was at the initiation of the president and Mrs Trump to go out of their way to say just how much they value this relationship and that's good news for Australia," the prime minister told reporters in Washington on Saturday (early Sunday AEST).

He described the state banquet under the stars in the White House Rose Garden as "the most magnificent, spellbinding, magical night crafted out of the imagination of Mrs Trump" and said he became "a bit weepy" when Mr Trump quoted a Mary Gilmore poem.

"I heard the start of the poem and I said that's, 'That's aunt Mary's poem! I'll have to tell him that when he's finished'.

"And he ended up telling me, so you know, that's the sort of detail that shows an affection."

After the flying stop in Ohio, Mr Morrison will move on to Chicago, where he is expected to dine with Illinois governor JB Pritzker.

Australian Associated Press