The two attackers were arrested in the Banka district, police said.
"We will arrest the third accused soon and will file charge sheet within 24 hours," Superintendent of Police Pushkar Anand told IANS over telephone from Banka, about 180 km from here.
The attack took place Tuesday evening when the woman and the youth were on a trip to Banka's Mandar Parvat (hill). They asked a group of shepherds for directions but were taken to a secluded spot instead and held hostage for about three hours.
"Both were held hostage and three men took turns to rape the woman. The assailants also looted cash from the duo before leaving," said Dhirendra Kumar, a district police official.
The victims later reached the Barahat police station and registered a first information report, police said.
Mandar Parvat is a small hill which is frequented by people for pilgrimage. It has many references in Hindu mythology as Mandarachal Parvat.