Both candidates, Uhuru Kenyatta and Raila Odinga, have their strongholds.
ELECTIONS | KENYA
After voting early Tuesday, Richard Ojijo, a 34-year-old fisherman, mounted his motorbike and drove a pair of elderly women to a polling centre so they, too, could cast their ballot.
"I want them to exercise their democratic right," Ojijo said of his impromptu election-day taxi service in Kenya's western city of Kisumu. "We want this thing to be successful."
Turnout is crucial in Tuesday's election, where the race between President Uhuru Kenyatta and his main challenger, Raila Odinga, is too close to call, and will likely come down to which side gets more voters out.
Both candidates have their strongholds: sultry, laid-back Kisumu is home to Odinga's Luo ethnic group who are sure to vote him into power, while Kenyatta can depend on fellow members of the Kikuyu people living in central Kenya to back him.
But with both candidates hoping to gain over 50 percent of the vote to squeak a first-round victory, some, like Ojijo, are leaving nothing to chance, and have made getting people to vote a personal quest.
A demand and a prayer
Polls opened at 6am but for the two hours beforehand, the sound of honking vuvuzelas, shrill whistles and motorcycle horns cut through the quiet streets as exuberant young men sought to ring the voters out.
"This is to tell people to come and vote!" said George Otieno, grinning as he blew an ear-shattering honk from his plastic horn.
The rangy 25-year-old was among thousands gathered at the city's sports grounds before dawn, where the atmosphere was more party than election: some had stayed awake all night waiting for polls to open, and were lubricating their wakefulness with booze.
One word, offered as both a demand and a prayer, was on the tips of the tongues of many of the thousands gathered at the field: "Change".
"We need change," said Otieno, a secondhand shoe salesman. "The cost of living is very high and the standard is very low. The government is just keeping money in its pocket and there is nothing for us."
The allegation of corruption is a perennial one in Kenyan politics, which for generations has been organised along ethnic lines with elected leaders expected to funnel state cash in the direction of their communities.
John Odundu, 40 and walking with a crutch, turned up to vote with his six-year-old daughter, Immaculate, dressed in a hot pink parka.
"She's a very strong supporter of Raila, she says she's coming to vote for him!" he joked.
Odundu is a Luo and had just voted for Odinga, yet he complained of the "tribalism" of Kenyatta's government, and insisted the opposition leader won his support through policies to help the poor, not ethnicity.
"If anybody could have come with his kind of policy, even if he was Kikuyu, we could still vote him," he said.
Voting is 'my passion'
Ronald Ngala, a 42-year-old real estate manager with a t-shirt reading "Kenya Forever" beneath his suit jacket, was itching to vote, and then to help others do the same.
After casting his ballots, Ngala hopped into his Toyota and headed for a nearby hospital, where he planned to collect ailing patients and take them to their polling stations.
Voting, he said, is "my passion".
The determination to vote -- and win -- has left many concerned that neither Kenyatta nor Odinga will be willing to accept defeat.
That's a dangerous prospect in a country where elections are frequently disputed and accompanied by bouts of deadly violence, and where martial language has become something of a lingua franca.
"When you are going into battle -- like me going to battle for Raila Odinga today -- we are sure we are going to win," said Ojijo. "It's not a question of why you will not win. We are sure we will win."
And with that, he prepared to set out again on his motorbike to find others who have not yet voted and ferry them to a polling centre.