Sept 20 (Reuters) - ICE cotton futures settled nearly unchanged on Wednesday in thin trading ahead of weekly U.S. export sales due on Thursday and as the dollar hovered near 2-1/2-year lows.

Cotton contracts for December settled down 0.02 cent, or 0.03 percent, at 69.25 cents per lb. It traded within a range of 69.05 and 69.73 cents a lb.

"The market is waiting for the crops to come in to see if they are as big as everybody says and also to see if the quality is good," said Peter Egli, director of risk management at British merchant Plexus Cotton. "If they're big and the quality is decent, (prices) might go a little lower."

Total futures market volume fell by 6,024 to 10,173 lots. Data showed total open interest fell 913 to 238,750 contracts in the previous session.

"The weakness in the dollar over the last few months has been underpinning commodities, including cotton, and that's been helping prices from falling too much," Egli said.

The dollar index was up 0.75 percent, but hovered near 2-1/2 year lows hit earlier in the month. The market awaited weekly export data from the U.S. Department of Agriculture (USDA) on Thursday.

"Merchants are kind of reluctant to sell higher grade (cotton) before the crop is in and mills don't want to pay prices this high or buy this quick. So, that is kind of impeding sales now a bit," Egli noted.

Certificated cotton stocks deliverable as of Sept. 19 totaled 2,414 480-lb bales, unchanged from 2,414 in the previous session.

(Reporting by Nithin Prasadin Bengaluru; Editing by Richard Chang)