CHICAGO, Oct 22 (Reuters) - Chicago Board of Trade soybean futures firmed on Thursday, hitting their highest in more than four years, with traders citing gains in the cash market and strong export demand for U.S. supplies as supportive factors.

A fast export pace also underpinned the corn market while wheat futures eased on technical selling after hitting their highest in nearly six years on Tuesday.

The most-active soybean futures contract peaked at $10.85-1/4 a bushel, its highest since July 14, 2016, but ended well off that peak after trading both sides of unchanged ahead of the close.

"The U.S. Agriculture Department came out with a fairly strong export sales report that heavily favored China digging into several of the commodity markets," said Terry Reilly, senior analyst with Futures International in Chicago.

The USDA report showed that weekly soybean export sales totaled 2.226 million tonnes, including 1.222 million tonnes destined for China.

Weekly export sales of corn totaled 1.832 million tonnes, up from 655,165 tonnes last week. China accounted for 433,500 tonnes of the total.

Chicago Board of Trade November soybean futures settled up 1-3/4 cents at $10.73-3/4 a bushel.

Private exporters reported the sale of 152,404 tonnes of soybeans to Mexico and 132,000 tonnes of soybeans to unknown destinations, the USDA said on Thursday morning.

CBOT December corn was 2-1/2 cents higher at $4.16-1/4 a bushel. On a continuous basis, the most-active corn contract hit its highest since Aug. 9, 2019.

CBOT December wheat futures were 7 cents lower at $6.22-3/4 a bushel, closing near session lows.

"Wheat was down all day, pushed lower on carry through from yesterday's liquidation," Charlie Sernatinger, global head of grain futures at ED&F Man Capital, said in a note to clients. (Additional reporting by Colin Packham in Sydney and Maytaal Angel in London; Editing by Susan Fenton, David Gregorio and Jonathan Oatis)