(New throughout, updates prices, market activity and comments to include U.S. trading; new byline, changes dateline, pvs SYDNEY/LONDON)

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

A fast export pace also supported 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.

"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, 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.

At 10:57 a.m. CDT (1557 GMT), Chicago Board of Trade November soybean futures were up 6-1/4 cents at $10.78-1/4 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 U.S. Agriculture Department 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 5 cents lower at $6.24-3/4 a bushel.

The wheat market also faced pressure from an improving rain outlook, although concerns remained about the parched soils in key production areas.

"Weather forecasters can see a little rain forming for dry Black Sea and U.S. grain regions at limits of the projection horizon," said Tobin Gorey, director of agricultural strategy, Commonwealth Bank of Australia. (Additional reporting by Colin Packham in Sydney and Maytaal Angel in London; Editing by Susan Fenton and David Gregorio)