Vote count in Colorado. (Photo: AFP/Getty)

Presidency now hinges on 4 battlegrounds. 

President Trump is leading in Pennsylvania (20 electoral votes), Georgia (16 electoral votes)  and North Carolina (15 electoral votes) while Biden is leading in Nevada (6 electoral votes). 

A candidate needs at least 270 electoral votes to win the election. 

US voters also cast their ballots for the Senate and the House of Representatives.

Senate seats are up for election once every six years. There are 35 seats up for this year's Senate elections including special elections in Arizona and Georgia. The Democrats need to flip four seats to gain control. The Republicans need to retain at least 21 seats to keep control.

All 435 House seats are up for election every two years. The Democrats gained control from the 2018 Midterm Elections with 232 seats. The Republicans need to flip 21 seats to gain control.