James Woody, 13, was pronounced dead on the scene, authorities said.
Witnesses said the Woody jumped into the river at Stratton State Park to retrieve a ball at around 7:30 p.m. Monday.
He swam far into the water and was swept away by a powerful 5 to 7 mph undercurrent. The strong current and presence of debris make this area off limits to swimmers.
Officials called off the search late Monday, and will resume searching this morning.
This is the second river search in as many weeks in Illinois.
Last week, 8-year-old Cashmere Castillo drowned in the North Branch of the Chicago River on the North Side of Chicago.
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