Observers report long lines at many polling stations at closing time. She led the country's recovery from a 14-year civil war and guided it through the Ebola crisis in 2014-15 that killed almost 5,000 Liberians.
Emerging reports indicate that the election is nearly certain to go to a run-off with 20 candidates contesting to succeed President Ellen Johnson Sirleaf, in a contest that completes the country's first democratic transition of power in more than 70 years.
The National Election Commission said local vote counting had ended after a largely smooth election.
"This is an important step toward achieving Liberia's first peaceful transfer of power from one democratically-elected head of state to another in decades". A runoff election, if needed, would come two weeks after that announcement. Voters commended her leadership, but also said they are ready for change when they lined up for Tuesday's historic vote. According to global observers, the vote has gone smoothly, despite its late start in some counties.
Responding to question from a journalist about how she felt after voting, she said: "I feel good and encourage all Liberians to vote right to move the country forward".
The retired proficient footballer turned politician who was a senator in his home country before his emergence as the successor of Ellen Johnson Sirleaf.