History of Isanti County

The word “Isanti” comes from a division of the Dakotas known as the Izatys, which may be translated to mean “Dwell at Knife Lake,” where they resided. Click here for a map of this area.

The name “ Rum River ” is thought to be a mistranslation of the Dakota word Wakan Wakpa meaning “Spirit River," which flows out of Mde Wakan, “Spirit Lake” or Lake Mille Lacs. In 1767 Jonathan Carver stopped at what is now Peninsula Point Two River Historical Park. He is credited with naming the Rum River.

Geology, Soils, & Topography

Isanti County is dominated by glacial deposits. They include morainic hills, outwash sand plains, glacial lake beds and numerous marshes, lakes and streams. Two kinds of glacial drift of different age and composition have been deposited in the County. The older is the middle Wisconsin drift which advanced from the northeast, commonly called the red drift due to the color of the material which is coarse textured, stony and low in lime.

The more recent drift was deposited by the Grantsburg sublobe of the Des Moines lobe as it advanced from the northwest. This material is grey when unweathered and is derived mostly from limestone and calcareous shale. It is less stony than red drift and is normally fine textured. Grey drift is relatively high in lime.

Lake Grantsburg, a lake formed at the same time as the advancement of the latest sublobe, provided the origin for the fertile, silty soils found along the northern border of the county.

Anoka Sand Plain

The Anoka Sand Plain which covers about 60% of the county was formed by the Mississippi River as it retreated from the Grantsburg sublobe. The sand plain is characterized by relatively smooth finger-like depressions, many small isolated marshes, and scattered dune-like knolls of wind-deposited materials. In most places, the sand overlays grey drift in thickness of sand that range from a few inches to many feet. The Zimmerman loamy fine sand and fine sands are the most common soils developed from these sandy glacial outwash deposits.

Morainic Hills

Several belts of morainic hills formed from material deposited during an early glacial period extend across the County. One of the most prominent is located in the southwestern corner occurs in Maple Ridge Township. This crest of the ridge which is the highest point in the county is 1,150 feet above sea level. Areas of rolling topography also occur in Stanchfield, Springvale, and Cambridge Townships. In Isanti and North Branch Townships the landscape is relatively smooth. Topography is rolling and steep again near the Chisago County line and rises 40 to 70 feet above the lakes and marshes.


The lowest elevation in the county is 875 feet above sea level at a point where the North Branch of the Sunrise River crossed the eastern boundary of North Branch Township. The maximum elevation change is 275 feet.

Isanti Co. comprehensive plan 2.0 The Earth page 15.

View additional historic information (PDF) from the Phase I Archaeological Reconnaissance of the Proposed Irving and John Anderson Park Extension Isanti County, Minnesota

By: Kelly Wolf, MA, RPA and Steven Blondo MA, Principal Investigator Blondo Consulting, LLC - November 17, 2016 FINAL REPORT