I like to gather all the companion Station locations. The ones on the map at Safe houses are given.
But I can imagine that some are on other locations where we can’t fast travel to. Maybe it is just the one where the mission ends. But if you find such a location, please note the coords and post it here if you like to contribute. 
34 Companion stations
33 In Safehouses
- Salthamn Shelter (A) => in hallway towards the exit
- Stenhaga Farm (A)
– - Asotugan Outpost (FL)
- F23 Överby Air Base (FL)
- Stora Dyrbo (FL)
- Broskulla (FL)
- Boo Bruk AB (FL)
- Sorken Command Bunker (FL)
- Ånnagruvan (FL)
– - Helgaryd (F)
- Hiker’s Barrack (F)
- Granhygget (F)
- Lennarts Marin (F)
- IGA (F)
- Kaptenvillan (F)
– - Torsberga Fort => directly outside (SC)
- Fiskeback (SC)
- Lannbacka (SC)
- Minken Command Bunker (SC)
- Knaperanna Farm (SC)
- Angerås Church (SC)
– - Uttern Command Bunker (M)
- Narkudden (M)
- Muskudden Port Complex (M)
– - Anl 118 Farela (ML)
- Nilssons Marinbygg AB (ML)
- Skvadern Command Bunker (ML)
- Aspenas (ML)
– - Hermalinen Command Bunker (NC)
- Kalkbrottet (NC)
– - Bjorntunate Hotel (HI)
- Tarnboda Skans (HI)
- Ronnhalla Emergency Shelter (HI)
Himsundsbryggan (HI) <= Map shows Companion Station but should have no Companion Station icon, because ther is no Station there. Caused by double name bug -Need fix
1 In Non-Safehouse location
- Vapenkussan at 1380, 3900 (A) Near Vesslan
Edit: Since this location is on Vesslan Command bunker grounds, it might be that a Companion Station icon is accidentally omitted from list of Stations at Vesslan.