This site is a clearing in a forest where Light Yagami buries the Death Note as part of his plan to clear his name and kill L. Before leaving the notebook, he has Ryuk and Rem acquire possession of the other's Death Note and instructs Rem to give the other notebook to a new owner.
After Misa Amane follows Light's instructions, she goes to the burial site and digs up the notebook. When she uncovers and holds the Death Note, she regains her memories of using it and the circumstances of meeting Light. Inside the Death Note, she also finds a letter from Light addressed to her instructing her on what to do next.
The burial site is located within an unspecified forest.
Not much of the forest is actually seen, but the burial site appears to be in a sizable opening within a dense patch of trees. At the time Misa recovers the notebook, the area is covered in thick fog.
The Death Note was concealed inside a box. Misa regains her memories of using it when she touches it.