Iain, who captained Ireland for the first time against France in this year’s Guinness Six Nations, made his international debut against South Africa in November 2012 and has won 60 caps to date for his country.
A Lions tourist in 2017, Iain succeeded Rory Best as Ulster captain in 2019. He has represented Ulster on 116 occasions.
“It has been a great honour to captain both Ulster and Ireland in recent times," said Henderson.
"Irish rugby is in a good place despite the disruption the sport has experienced during the pandemic. As professionals we have been in a privileged position to be able to continue playing and I know we all hope to see supporters back in the Aviva and Kingspan in the near future.”
