The Northern Waste was a cold and icy region in the far north end of Middle-earth, located above Mount Gundabad and the Ered Mithrin.The two main areas of the Northern Waste are Forodwaith and Forochel, both had the same cold weather. It was a vast region of mostly snow and ice; however it did have several great frozen lakes, and a few unfrozen lakes that had bitterly cold waters. The two main areas of the Northern Waste are Forodwaith and Forochel, both had the same cold weather. However there was life in this freezing cold region.
The Cold-drakes of the North, which drove the Dwarves out of the Grey Mountains, came from the Northern Waste. The Drakes killed Dain I and his son Frór outside their Halls in the Grey Mountains. The Dwarves then fled to Erebor and the Iron Hills It is likely that the "Goblins and Hobgoblins" that later colonized the Ered Mithrin drove most of the Cold-drakes back into the Northern Waste.
According to Frodo's poem "When evening in the Shire was grey" it mentions that Gandalf had traveled to the Northern Waste. What his business was up there is unknown for it mentions it nowhere else in Tolkien's work. There were also men up in the wastes called the Lossoth. They were a hardy folk fit to survive in the cold snowy regions of the north. It is possible that some of them were in league with Angmer because the Witch King had recruited men into his service but that is only a speculation. The people lived mostly in tribes and they likely fought with eachother over land and resources as did all folk in the world. The Lossoth never involved themselves with the world outside their frozen lands and played no known significant role in the wars until King Arvedui who was the last king of Arnor came out of hiding from an abandoned Dwarf-mine near the tip of the Northern Ered Luin and asked for aid from the Lossoth of Forochel. He was able to convince them to aid him and gave them the ring of Barahir. Cirdan eventually sent ships for him. On his departure day, the Lossoth warned him that a storm was comming and urged him not to go but he payed little attention to it and he did indeed perish in the storm and sank to the bottom of the sea along with the palantir of the North. This indeed proves that the Lossoth had very keen senses.