Since Hawaii became a state in 1959, that state has had only 5 senators. Daniel Inouye who passed away on December 17, was senator for 50 of those years making him the senior member of the U.S. Senate and the second longest serving senator in history. The late Robert Byrd of West Virginia had the most years, 51 years.
Now Lt Gov Brian Schatz will finish out Inouye's term and become only the 6th person to serve from Hawaii. Of the (now) 6 senators all but one have been democrats. The lone republican to represent Hawaii was Hiram Fong who was the first to be elected after statehood in 1959 and he served until 1977.