People's State Bank of Parshall, ND opens it doors.
The Petersen family purchased controlling interest in Lakeside State Bank and today the family remains Cornerstone Bank's largest shareholder.
The Petersen family expanded into Watford City creating McKenzie County Bank.
Cornerstone Holding Company, Inc. began when six Fargo based successful entrepreneurs purchased Citizens State Bank in Enderlin.
The Petersen family acquired Peoples Bank in Makoti, Plaza, and Parshall, which has roots back to 1936.
On December 31, 2014, Cornerstone Holding Company, Inc. and Lakeside Holding Company merged.
March 2016, Cornerstone Bank expanded, into the Dickinson market with the opening of a full service bank location.
June 2016, Cornerstone Bank further expanded, by purchasing the First Interstate Bank location in Sioux Falls.
December 2018, the Sioux Falls team moved into their brand new bank building located at the corner of 69th and Louise.
August 2019, Lakeside Insurance Agency, Inc. became Cornerstone Insurance Services, Inc. Located in Cornerstone Bank in New Town.
January 2022, the Bismarck team moved into their brand new bank building.