Originally, the bank began in Dunn Center as The Union Bank of Dunn Center and was incorporated on July 28, 1924. Some of the owners and directors were H.E. Skange, Dr. V.H. Stickney, H.P. Johnson, T.A. Tollefson ,and R.H. Johnson. The owner of First National Bank in Dickinson, A.P. Nachtwey and the owner of a bank in Hebron, Herman Leutz also had a part in getting the Dunn Center bank on its feet
The directors decided to sell shares at $100.00 each for a total capital of $15,000.00. O.T. Evenson was hired as the assistant cashier at a salary of $125.00 per month, plus a benefit of 25% of the net insurance commissions.
In 1948, the bank was sold to H.M. Weydahl. In 1949, he moved the charter to Halliday and changed the name to The Union Bank of Halliday. Weydahl's son Earl, sold the bank to Gerald Bogers and Adolph Walth in 1967 when the total assets of the bank were $2,100,000.00. Bogers began working for the bank in April of 1952 and retired as President in 1982.
Adolph Walth passed away in 1973. Adolph's son, James moved from Grand Forks to Halliday in 1973. In 1979 Gordon Hoffner purchased an interest in the bank. In 1982 James Walth and Gordon Hoffner purchased the bank shares owned by Gerald Bogers. James Walth was President of the bank from 1982 until 1987. James Walth then sold his stock in The Union Bank to Gordon Hoffner and some local investors in July 1987. Gordon's son, Wayne Hoffner became President in July 2010. Gordon Hoffner retired as Vice President in February 2014.
The Union Bank charter was moved to Beulah, North Dakota in 1995. A third location was opened in Hazen February 14, 2005. The Union Bank purchased First State Bank of Wilton August 1, 2013. The Bank of Glen Ullin merged into The Union Bank October 30, 2020.
2022 year-end combined total assets of the banks in Halliday, Beulah, Hazen, Wilton, and Glen Ullin were about $206 M.