World No.6 Lee shot a final-round 70 and got within one shot of the lead on the back nine but In pulled clear with a 66 to win at 16 under.

In, who started the final round two strokes off the pace, carded seven birdies against a lone bogey to win from England's Charley Hull who shot a 71.

World No.1 Sung Hyun Park offset a pair of bogeys with five birdies for a 69 that left her tied for third with Lee, Ariya Jutanugarn (71) and overnight co-leader Danielle Kang (72).

Defending champion Jin Young Ko had eight birdies in a bogey-free round for the day's lowest score of 64 to finish seventh.

Chun poses with the trophy after winning the Hana Bank Championship in South Korea. PHOTO: JUNG YEON-JE/AFP/Getty Images.

With nine wins on the Korean women's Tour before making the switch to the United States for the 2016 season, Chun's popularity remains undimmed at home and Sunday's galleries were again swelled by her huge army of followers.

"I'm so happy to win in front of these fans," a tearful Chun told Korean television, adding she hoped it would mark a "turning point" after two winless seasons.

World No.1 Park was disappointed not to have laid down a challenge on the final day.

"As I mentioned earlier, this was a course I was confident with and in the past had scored very well here, and I really wanted to win. But today I wasn't able to bring my A game," she said.

The US tour continues its end-of-season Asian swing next week in China with the inaugural Buick LPGA Shanghai.