Minn. Stat. § 103G.131
Subd. 1. Water located in one county.
Notwithstanding any other law to the contrary, an action for declaratory judgment that is brought under chapter 555 by or against the commissioner must be venued in the county where the water, watercourse, or water basin is located, if the water, watercourse, or water basin is located in one county. This section applies to actions to determine the validity of the commissioner's final decision regarding:
Subd. 2. Water located in more than one county.
If the water, watercourse, or water basin is located in more than one county, then the venue is the judicial district where the majority of the water, watercourse, or water basin is located.