On March 4, Seth Bodnar declared as an independent candidate for U.S. Senate from Montana. See this story.
The highest percentage ever received by a U.S. Senate candidate in Montana who was not a Republican or Democratic nominee was in 1912, when the Progressive Party’s candidate, Joseph M. Dixon, polled 32.1%, ahead of the Republican nominee. The 1912 U.S. Senate election was technically an advisory vote, because at the time the U.S. Constitution still required legislators to choose Senators. Montana and a few other western states held advisory U.S. Senate votes to influence whom the legislature should choose.