The Senate Republican caucus said Linwood Palmer Jr., who was in his mid 80s, died Thursday.
Palmer was first elected to the Maine House in 1947 at age 24 and went on to the Senate in 1950. He returned to the House in the 1970s and served two terms as minority leader.
Palmer won the GOP gubernatorial nomination in 1978 but lost to Democrat Joseph Brennan in a three-way general election.
A memorial service will be held Thursday at the First Baptist Church of Nobleboro.