Nixon was heading to St. Charles County on Friday for an aerial look at the high water and the condition of levees.
The National Weather Service said the river had crested in the St. Louis area and the Illinois towns of Grafton and Alton further north.
Missouri Senator Roy Blunt says the federal government has gotten too preoccupied with habitat restoration, instead of flood control.
Flooding and concerns about water quality have prompted the closings of several public swimming beaches in Missouri.
The National Weather Service says there are multiple spots of potential failures along that levee between Portage Des Sioux and West Alton.
The rivers appear to have crested.
Warning sirens blared in West Alton Monday night as 590 residents were advised to evacuate because of a levee breach in northeastern St. Charles County.
More than $73 million in federal aid has been approved so far to help Illinois communities hurt by April’s floods.
According to HomeInsurance.com, Missouri homeowners pay over $300 more each year than residents of Illinois and Iowa but $400 less than Oklahoma residents.
Forecasts call for the river to crest Tuesday at 34.5 feet, nearly four feet higher than April’s crest, but lower than earlier predictions.