Hillary Clinton declared herself the Democratic presidential nominee on Tuesday.
If confirmed at the Democratic National Convention in late July, this would make her the first woman in the US's 240-year history to lead a major party in the race to the White House.
The former first lady, US senator and secretary of state celebrated at a raucous event with supporters in Brooklyn, New York.
She placed her achievement in the context of the long history of the women's rights movement.
"Thanks to you, we have reached a milestone. We all owe so much to who came before."
Clinton declared her campaign had broken "one of the highest, hardest glass ceilings."
On Twitter, she said:
To every little girl who dreams big: Yes, you can be anything you wanteven president. Tonight is for you. -H pic.twitter.com/jq7fKlfwGV
— Hillary Clinton (@HillaryClinton) June 8, 2016
It was a historic day for another reason.
Exactly eight years ago on the same day, Clinton had conceded the race for Democratic nomination to then senator Barrack Obama.
Clinton, 68, spoke shortly after beating Sanders in New Jersey's nominating contest, expanding her lead in the delegates needed to clinch the nomination and setting up a five-month general election campaign against Republican nominee Donald Trump in the November 8 election.
New Jersey was one of six states holding contests on Tuesday, including California, the big prize where Clinton was still at risk of an embarrassing loss to Sanders as she heads into the campaign against Trump.
Polls in California closed at night, and news networks said the race was too close to call.
There was jubilation on social media, especially from those who support greater participation of women in all walks of life.
— VIV (@VIviP22) June 8, 2016
#HillaryClinton makes us believe in ourselves - a woman can do anything she wants to. It takes non-stop determination.
— Nazrana Yousufzai (@NazranaYusufzai) June 8, 2016
In her speech, Clinton appealed to Sanders supporters to join her and said the Democratic Party had been bolstered by his campaign to eradicate income inequality, which has commanded huge crowds and galvanised younger voters.
Clinton edged Sanders out, especially among older voters, with a campaign focused on building on the policies of her fellow Democrat, President Barack Obama.
Although Sanders will be unable to catch Clinton even if he wins the primary in California, America's most populous state, a triumph there could fuel his continued presence in the race and underscore Clinton's weaknesses as she battles Trump.
The White House issued a statement saying Obama had called both Clinton and Sanders on Tuesday.
It said he congratulated her on securing the delegates necessary to clinch the nomination.
A Reuters/Ipsos poll released on Tuesday showed Clinton leads Trump by 10 percentage points nationally as they launch their general election battle, little changed from a week ago.
Many Trump supporters expressed anger at Clinton's success.
Clinton's victories ensured she will have a lead in the pledged delegates won in nominating contests.
She also has the support of the majority of superdelegates, party leaders who are free to back any candidate.
Trump, who became the Republican Party's presumptive nominee last month – outlasting 16 Republican challengers – is struggling to get the party's leaders solidly behind him after a bitter primary campaign during which he made a series of controversial statements directed at Muslims, Latinos, women and the disabled.