Gambians were due to head to the polls on Saturday, in the first presidential election in the tiny West African nation since former dictator Yahya Jammeh fled into exile.
The voting will be closely watched as a test of the democratic transition in the country, where Jammeh ruled for 22 years after seizing power in a bloodless coup in 1994.
The ex-autocrat was forced into exile in Equatorial Guinea in January 2017 after Adama Barrow, then a relative unknown, defeated him at the ballot box.
President Barrow, 56, is now running for re-election, and faces five other candidates.
Political veteran Ousainou Darboe is considered the leading opposition candidate.
The 73-year-old is a lawyer who has represented opponents of Jammeh, and who ran for president against the former dictator several times.
He also served as foreign minister and then vice president under Barrow, before stepping down in 2019.
Many voters in the impoverished nation of more than two million people are hoping for an improvement in their living standards.
The Gambia, a sliver of a land about 480 kilometres (300 miles) long, which is surrounded by Senegal, is one of the poorest countries in the world.
About half of the population live on less than $1.90 per day, the World Bank says.
The tourism-dependent economy in the former British colony was also dealt a severe blow by the Covid pandemic.
Barrow is running on a continuity ticket, pointing to infrastructure projects completed under his watch, as well as increased civil liberties.
Polls are due to open at 0800 GMT in The Gambia, and set to close at 1700 GMT.
Each candidate has their own ballot box at Gambian polls, and voters choose their preferred politician by dropping a marble inside one of the boxes.
The unusual voting method is a response to low literacy rates in the country.
Initial results in the one-round presidential election could be announced as early as Sunday.
Questions over Jammeh's continuing role in politics, and his possible return from exile, have been central themes in the run-up to the election.
The 56-year-old former dictator has also sought to influence the vote, calling in to address rallies of supporters during the campaign period.
Jammeh retains significant political support in The Gambia.
Another political camp, however, is pushing for criminal charges against Jammeh for alleged abuses committed under his rule.
Barrow set up a truth commission to probe the alleged abuses after coming to office.
Before hearings ended in May, it heard testimony from hundreds of witnesses about state-sanctioned death squads, witch hunts and forcing bogus cures on AIDS patients, among other abuses.
The commission recommended the government pursue criminal charges in November, in a final report that it handed to Barrow without releasing to the public.
The names of the officials against whom charges were recommended were also not released.
Criminal charges are politically sensitive given Jammeh's following, however.
There are also growing concerns about Barrow's enthusiasm for prosecutions, despite previous rhetoric that was tough on Jammeh.
In September, for example, Barrow's NPP party announced a pact with Jammeh's APRC -- in a controversial move that was viewed as an electoral ploy.
Jammeh said that decision was taken without his knowledge, and his supporters have formed a rival party. But rights groups fear the pact will diminish chances of a trial.