The highway previously existed as State Route 69.

The highway comes to an end on Main Street in the middle of the town.

[2] An unimproved road linking Manhattan westward to State Route 8A (now SR 376) existed as early as 1936.

[4] The route was improved to a gravel surface by 1946[5] but would not actually be paved until 1976.

The SR 69 designation was eliminated and replaced by State Route 377 on July 1, 1976;[7] maps began to reflect this change in 1978.