The Minnesota Historical Society (MNHS) has a great, free collection of digitized newspapers. You can find the collection through their website here. The platform to view and search through pages has changed recently, so check it out if you haven’t visited in a while.
The collection contains newspapers published between 1856 and 2009. 1856 has just a couple of issues, but the next year has 66. Then the issues per year generally increases, to over 1000 issues per year in 1877 and over 2000 issues per year in 1890. After 1922 there are fewer than 106 issues per year, due to copyright law. Additional newspapers from those years can be viewed in person at the Minnesota History Center in Saint Paul.
The vast majority of the newspapers are from Minnesota. Forty-one of Minnesota’s 87 counties are represented. The top five cities represented are Minneapolis, Saint Paul, Duluth, Bimidji, and Rochester. There is a convenient map that displays newspaper coverage. Select a city to see a list of newspapers and years covered.
In addition to Minnesota, there are small collections from five nearby states. There are 1595 issues from Chicago, Illinois; 947 issues from Santee, Knox County, Nebraska; 623 issues from Greenwood, Charles Mix County, South Dakota; 56 issues from West Superior, Wisconsin; and 21 issues from Westerville, Franklin County, Ohio.
You can search through all of the content, using up to five search terms. Select an issue from the search result to get directly to a page in that issue with search results, which will be highlighted in yellow. Don’t forget to also browse through issues, because OCR isn’t perfect.
I have had a few problems when viewing search results; they start to always bring me to the first page of the issue and don’t highlight where the search term is found. I have started from the top opening the Newspaper Hub and starting my search over, and that has solved the problem for me.