Voters in Pennsylvania headed to the polls Tuesday to cast their votes in a critical presidential swing state that also is the setting for one of the country's most contentious Senate races.

The winner in the presidential race will take the state's 19 electoral votes.Polls closed at 8 p.m. local time.

State significance

Pennsylvania's importance this election can't be overstated as the nation's preeminent, with both parties at times referring to victory in the state as essentially the whole ballgame for the presidential race at large.

The anchor of the so-called Blue Wall -- the three Rust Belt states that hadn't gone for any Republican between 1988 and 2016 -- Pennsylvania went for former President Donald Trump by more than 44,000 votes in 2016 before President Joe Biden took it back by more than 80,000 votes in 2020.

Democrats' main base of support lies in Philadelphia and Pittsburgh, the state's two urban centers, while Republicans have dominated in the rural areas in between. However, Vice President Kamala Harris had been campaigning in certain Republican-leaning areas to try to eat into the GOP advantage there.

Democratic Sen. Bob Casey is also running for a fourth term against Republican Dave McCormick in a race that Republicans view as a top flip opportunity as the GOP tries to win Senate control.

Counties are colored red or blue when the % expected vote reporting reaches a set threshold. This threshold varies by state and is based on patterns of past vote reporting and expectations about how the vote will report this year.