Igance and Wabigoon Lake Ojibway Nation are still in the running as a host site for an underground repository for used nuclear fuel.
The Nuclear Waste Management Organization says Blind River and Elliot Lake are no longer part of the site selection process, trimming the number of candidates to five.
Officials say technical studies and engagement with people in the area identified a number of factors that would pose challenges, including limited access and rugged terrain.
A low potential to develop partnerships needed to implement the project was also cited.
The process started with 22-interested communities.
Ignace is now joined by Manitouwadge, Hornepayne, South Bruce and Huron-Kinloss in ongoing studies.
Initial borehole drilling and core sample testing has taken place at the Ignace site.