Minn. Stat. § 373.30
A county with a population according to the 1960 federal census of less than 100,000 which has a population of over 100,000 according to the 1970 federal census may continue to use authorities granted to counties of under 100,000 population notwithstanding the change in population. Statutory limitations and mandatory provisions of law relating to counties of over 100,000 population shall not apply to counties which had a population according to the 1960 federal census of less than 100,000 population. Statutory limitations and mandatory provisions of law applicable to counties of under 100,000 shall continue to apply to counties which according to the 1960 federal census had less than 100,000 and which according to the 1970 federal census have a population in excess of 100,000. Application of legislation passed in 1969 or later shall not be affected by this section.
Minn. Stat. § 373.30
1969 c 254 s 1; 1984 c 629 s 1