 The Saint Francis River also rises in Benton and flows southward through the central part of Sherburne County, discharging into the Elk just north of Big Lake.The terrain of Sherburne County consists of low rolling hills, partially wooded, heavily sprinkled with lakes, ponds and depressions.The soil of Sherburne County contains considerable sand and gravel due to glacial activity in past epochs, and thus is less suitable for agriculture than much of Minnesota.