Democratic primary results map: See how the US votes in 'Big Tuesday'

Six states hold contests to select party’s nominee as race comes down to Joe Biden and Bernie Sanders

Bernie Sanders and Joe Biden compete for the 202 Democratic presidential nomination. (Reuters)

Voters in six states are casting their ballots to select the Democratic presidential nominee, with a field that is now essentially narrowed to front-runners Joe Biden and Bernie Sanders.

Following Super Tuesday, the results from 10 March primaries account for the second-biggest haul of delegates that will select the nominee to the lead the party to face Donald Trump in November. The candidates will compete for their share of 352 delegates across Idaho, Michigan, Mississippi, Missouri, North Dakota and Washington state.

Michigan — which carries 125 pledged delegates — has emerged as a key battleground state as the former vice president and senator from Vermont vie for the state’s diverse electorate, including blue-collar and working-class black and white voters and suburban dwellers.

Senator Sanders narrowly defeated Hillary Clinton in that state in 2016, when she also was defeated by candidate Trump in the general election.

But the former vice president’s ascendant campaign -- following Super Tuesday victories and strengthened by support from his former Democratic rivals who have withdrawn from the race -- could change Mr Sanders’ trajectory in the Midwest.

Mr Biden has collected 670 pledged delegates while Mr Sanders has 574. Hawaii Congresswoman Tulsi Gabbard, who remains in the race, has received only two delegates. It will take a minimum of 1,991 delegates to win the party’s nomination.

Idaho polls close at 10pm EST, Washington’s poll close at 11pm EST, and all other polls close at 8pm EST.