Grand Rapids is a city in Itasca County, Minnesota, United States. The population was 10,869 at the 2010 census. It is the county seat of Itasca County.The city of Grand Rapids is named for the 3.5-mile long local rapids in the Mississippi River, which was the uppermost limit of practical steamboat travel during the late 19th century. Today, those rapids are hidden underneath the dam of the Blandin Paper Mill.