The Henderson County levee was breached at about 5 a.m.
McCloud says hundreds, if not thousands, of acres of farmland are affected.
Hancock County spokeswoman Kathleen Dougherty says low-lying river communities, including Pontoosuc, are largely under water.
McCloud says there have been more than a half dozen levee breaches in Illinois in the past week or so, including in Keithsburg in Mercer County.
