MN 210 was authorized on July 1, 1949 between then-
US 61 (now
MN 45) in Carlton and
MN 23 in Duluth, The original eastern segment was subsequently renumbered as part of
MN 39 in 1956. When US 210 was removed in 1970, the highway was redesignated MN 210. The historic original route of MN 210 between Carlton and Duluth was changed back at this time as well. MN 210 runs along the original mainline of the
Northern Pacific Railway as built westward from Carlton to
Staples. Between
Henning and
Breckenridge, the highway runs along a former branch line of the Northern Pacific Railway. Most of the branch line has since been abandoned. The western section of the highway, between Breckenridge and
Fergus Falls, was originally part of Minnesota
Constitutional Route 3. Between Fergus Falls and Henning, the highway was part of Constitutional Route 36. The section between Carlton and Motley was part of Constitutional Route 2.
US 210 {{infobox road small MN 210 from Carlton to Motley, the eastern portion of the present day highway, was originally part of
U.S. Route 210 from 1926 to 1970. During 1970, US 210 was
decommissioned from Carlton to Motley and re-designated MN 210 that same year. US 210 was originally commissioned in 1926 by the
American Association of State Highway Officials, as one of the original US Highways. In the 1934 numbering plan, US 210 from Carlton to Motley was slated to be re-designated as
U.S. Route 208. The road was almost re-numbered because of a routing change in its parent road (
US 10). Ultimately, US 10 was routed along former
US 10N. US 208 was shown on some maps in the mid-1930s running from Carlton to Motley, but the number was not officially commissioned or signed, and US 210 kept its number. ==Major intersections==