By the 1960s it was decided that the company's headquarters should be located within its service territory, in Bismarck, the largest town on the system, and the relocation was completed in 1968.

In 1992, it acquired its first aggregates-mining company in central California, and has continued to expand its construction materials business .

[3] After the end of the lawsuit, MDU refocused on the growing demand for electricity and gas within its newly expanded territory and the necessary system improvements.

[8] Additionally, OSHA cited and fined Loy Clark for safety violations as a result of this incident.

[10] Cascade Natural Gas Corporation, serving parts of Oregon and Washington, was acquired by MDU Resources in 2006.

[11][12] Intermountain Gas Company, serving parts of Idaho, was acquired by MDU Resources in 2008.

[13] In 2023 MDU spun off Knife River Corporation, which provides construction materials and contracting services, including aggregate, asphalt, building materials, cement, construction services, liquid asphalt, and ready-mix concrete in 17 states, into a separate publicly traded company.