In Days Gone there are 2 points of no Return.
The first Point of No Return is at the end of the third region called Lost Lake. It’s the start of mission Riding Nomad Again.
The second Point of No Return is at the end of the fifth region called Crater Lake. It’s at the mission Shadow of Death.
In both cases the game will warn you with an onscreen prompt telling you that you’ve reached the Point of No Return and will get locked out of certain regions, their camps and merchants.
But can you return to the northern regions later on?
Luckily, the answer is YES, you can get back to all regions after the story. What the game doesn’t tell you is that these “Points of No Return” are only TEMPORARY. You do get locked out of these regions until the end of the story but after this you can go back to all camps to finish any encampment jobs (side quests) you have left. You can also still gather the collectibles and finish Nero Checkpoints, Hordes, Ambush Camps etc.
So nothing is missable. The game just doesn’t explain this very well and makes it sound like these points of no return lock you out permanently, but that is not the case at all.
For more Days Gone Tips & Tricks check out the full Days Gone Wiki & Strategy Guide.