Full-back Hogg will lead his country after Greig Laidlaw announced his retirement from international rugby last month.
As well as appointing a new skipper, head coach Townsend has also brought in some fresh faces following Scotland's failure to advance from their pool at the Rugby World Cup.
Tom Gordon, Kyle Steyn, Ratu Tagive, Luke Crosbie, Nick Haining and Alex Craig will be hoping to win their first caps.
Matt Scott and Rory Sutherland have been recalled to a 38-man squad along with Cornell du Preez.
Townsend said: "We've put a bigger emphasis on form as a guide for our selection, with those picked backed to go out and grab their opportunity.
"A number of young players have broken through at their clubs, while the bulk of the squad [23/31] from Japan has been reselected based on some strong individual performances and huge effort throughout our World Cup camp.
"We're on to our next campaign now and it’s going to be very tough given the competition we face. Ireland have only lost one championship game at home in the last five years, and England were in great form in Japan."
Scotland face Ireland at the Aviva Stadium in their first match of the Six Nations on February 1.
Forwards: Simon Berghan, Jamie Bhatti, Magnus Bradbury, Fraser Brown, Alex Craig, Luke Crosbie, Scott Cummings, Allan Dell, Cornell du Preez, Zander Fagerson, Grant Gilchrist, Tom Gordon, Jonny Gray, Nick Haining, Stuart McInally, WP Nel, Jamie Ritchie, Rory Sutherland, Ben Toolis, George Turner, Hamish Watson.
Backs: Darcy Graham, Chris Harris, Adam Hastings, Stuart Hogg (captain), George Horne, Rory Hutchinson, Sam Johnson, Huw Jones, Blair Kinghorn, Sean Maitland, Byron McGuigan, Ali Price, Henry Pyrgos, Finn Russell, Matt Scott, Kyle Steyn, Ratu Tagive.