Copper Ore can already be found in the beginning area of the game. While most of all copper can be found in the Farbane Woods, there is one specific location that you could go to if you are in real need of some copper ore.
As usual, Copper can mostly be found near roads, rivers and even some larger formations that you can only destroy if you have explosives. The best spot to farm copper ore is by visiting the Copper mines. This can be found in the centre of the map of Farbane Woods.
Inside the mines, there are a few copper veins you can collect, making it possible to go back home with an inventory full of them. Do keep in mind that some low-level NPCs are walking around and that there is a world boss inside the mines.