Over the weekend, the eastbound detour was extended to more than 200 miles because the original detour route has been overcome by floodwaters.
The National Weather Service says the river has crested where it crosses I-40, but it could be days yet before the roadway is passable. Water levels in the Mississippi river must first recede before the White River can drain.
The White River broke a record set in 1949, according to the National Weather Service. The previous record was 37.3 feet, the agency said.
"That is first time in the history that highway has been closed," said Tommy Jackson, spokesman for the Arkansas Department of Emergency Management in Little Rock. "That is a major trucking corridor between Little Rock and Memphis."
Jackson said with the Mississippi rising, the White River has no place to go, so flooding will probably last in Arkansas through next week.
The Mississippi is nearing a record levels in Memphis, and could threaten riverside oil refineries.
The Memphis river gauge was at 47 feet on Sunday afternoon, according to the National Weather Service. The record at Memphis is 48.7 feet set in 1937.
"The high water, and consequently the increase in river currents, will affect tanker traffic for the delivery of crude oil and the loading of petroleum products," Andy Lipow, president of Lipow Oil Associates LLC in Houston, was quoted by Bloomberg.
Some refinery locations may be flooded by the rising water, causing reductions in crude processing rates and consequently an impact in supply, be noted. "The New Orleans-Baton Rouge region has 11 refineries with a combined capacity of 2.5 million barrels a day, or 13 percent of U.S. output."
Click here for maps of the recommended detours around the flooded areas of Interstate 40 in eastern Arkansas.