Days Gone has 18 Nero Research Sites. They give you Nero Injector stat upgrades to increase Health, Stamina and Focus. This guide shows all Days Gone Research Site Locations.

As an added bonus you'll find one Nero Intel at each of these sites to help you get a higher completion rate.

The way you'd normally unlock the Research Sites on the map is to capture the Ambush Camps. This will give you at least on Nero Research Site on the map. Then listen to the Nero Intel from that Research Site and it will give you the next Research Location. Repeat for all other regions. Of course with this guide you can skip all that and head straight to the marked spot. When you get close to the Research Site it will get marked on the world map.

Most of them are either in Freaker Caves or require you to make long jumps with the motorcycle. Go to the caves at night (at day the Freakers sleep in there and would kill you). For the bike jumps you should first get a Nitrous Upgrade. If a jump is too far get better upgrades to increase your top speed.

None of these are missable! After the story there's free-roam and you can go back to all regions and finish up any side activities and collectibles you have left. It's worth noting that there are two temporary points of no return. One at the end of 3rd region "Lost Lake" and one more at the end of 5th region "Crater Lake". This will lock you out of some regions until the end of the story. Then after the story the whole map opens up again.