|Former Census-designated place (CDP)|
|Elevation||1,444 ft (440 m)|
|Time zone||Central (CST) (UTC-6)|
|• Summer (DST)||CDT (UTC-5)|
|GNIS feature ID||660676|
Arnold is a former census-designated place (CDP), which was located in Saint Louis County, Minnesota, United States. The census-designated place of Arnold was located entirely within the former Rice Lake Township, adjacent to the north side of the city of Duluth. Rice Lake Township was incorporated as the city of Rice Lake on October 22, 2015, thus rendering the census-designated place of Arnold to no longer exist.
The name "Arnold", as a place of residence, had been seldom used in the present day by the younger generations. Since about 1970, those who reside in this area had identified themselves as residents of Rice Lake or Duluth. The CDP name "Arnold" was used only for statistical purposes for the U.S. decennial census count of population.
According to the United States Census Bureau, the former CDP of Arnold had a total area of 11.6 square miles (30 km2); 11.6 square miles (30 km2) was land and 0.1 square miles (0.26 km2), or 0.60%, was water.