There were five candidates, including Zaini Abdullah, a former rebel who appeared headed for victory, according to quick count results which are based on samples of votes at some polling booths. More than a dozen others ran for district chiefs and mayoral posts. Official results will be announced next week.
Aceh is the only region in the nation of 240 million ruled by Islamic law, sparking debate ahead of the poll as to how strictly it should be enforced. But on the forefront of most voters' minds was peace, stability and ways to ensure continued economic growth after the tsunami helped speed an end to a 30-year civil war.
"I don't care who wins," said Teuku Sayed Azhar, a farmer who lost his brother and dozens of friends and neighbors in the war that claimed more than 15,000 lives.
"As long as they make sure Aceh doesn't fall into that dark hole again.
"Nowadays I can go into my field anytime, day or night," he said. "That's what matters most ... that our lives can continue to improve. "
This is the second election in the province since a 9.0 magnitude quake triggered a tsunami that killed 230,000 people in a dozen nations—three quarters of them in Aceh alone.
Saying they didn't want to add to people's suffering, both rebels and the army agreed to lay down their arms.
However, tensions have flared anew in recent months, mostly between past and former members of the Free Aceh Movement, or GAM, sometimes erupting in violence.
Incumbent Irwandi Yusuf, a former separatist who shocked the world by winning the governorship in 2006, is running as an independent.
His main challenger was Abdullah, backed by many former GAM members.
Each side has accused the other of intimidation.
"I will accept the result, whoever wins," said Yusuf. "As long as the election is free and fair ... that's how it should be in a democracy."
The Indonesian Survey Institute said Abdullah, a former deputy chief of GAM who lived in exile in Sweden during the civil war, appeared headed for a landslide win.
He had 55 percent of the vote compared with 29 percent for Yusuf, according to the quick count results, which had a margin of error of 1 to 2 percentage points.
The election is being closely watched in part because Aceh's success in integrating former rebels into the political landscape is seen as a potential model for wartorn countries.
The province with more than 4 million people was also one of the biggest recipients of international aid, with billions of dollars arriving after the tsunami. Much more work still needs to be done to rebuild, however, and stability is key.
Eka Putra Herlambang, waiting with his wife to cast his ballot in the provincial capital of Banda Aceh, said what he wanted most was "peace and development."
Andiyan, a housewife, nodded. She would like to see Islamic law—one of the concessions made by the government as part of the deal to end the fighting—more strictly enforced.
"But yes," she said. "Most important is peace."
Associated Press writer Niniek Karmini contributed to this report from Jakarta.