Mr MacCormick, was elected to the House of Commons in the first 1974 general election, and represented the constituency until 1979.
He was one of a generation of nationalist politicians who helped make the SNP into a mainstream force in the 1970s.
Mr MacCormick died on Friday night, the day after voting in the independence referendum.
He lived in Oban, and was a former teacher at the town's High School.
Education Secretary Michael Russell described him as a "remarkable man" who had been part of a "vastly influential Scottish political family which helped to build our modern nation".
Mr Russell, the SNP MSP for Argyll and Bute, added: "The parliamentary success of Iain and his colleagues in the two elections of 1974 -  returning first seven and then 11 MPs - by its pressure at home and at Westminster secured the first devolution referendum in 1979 and ultimately led to the establishment of a Scottish Parliament in 1999.
"Although he left the SNP for a time in the 1980s he subsequently returned to it and he always wanted to see Scotland flourish.
"It is a measure of his passion for change and his extraordinary, determined character that despite being ill and in hospital until the end of last week, he insisted on going in person to vote 'Yes' in the referendum on Thursday.
"I spoke on a 'Yes' platform in Oban with him earlier this year and he remained a fine orator whose keen mind got to the very heart of any issue."
Iain MacCormick, the former SNP MP for Argyll, has died at the age of 74.