The Shire is the fictional land where Frodo lives at the beginning of J.R.R. Tolkien’s The Lord of the Rings.
The Shire is a settled region in the northwest of Middle-earth, inhabited mainly by Hobbits. It contains communities such as Hobbiton, Bywater, Tuckborough, and Buckland. Frodo’s home is Bag End, a comfortable hobbit-hole on the Hill in Hobbiton.
The Shire represents the familiar, agricultural world that Frodo and his companions leave behind. Its quiet lanes, gardens, inns, and predictable customs contrast sharply with the war, ruins, and wilderness encountered during the quest. Tolkien nevertheless gives the Shire its own political and social history, including the authority of the Thain and the controversial rule of Lotho and later Saruman.
The Shire is not the same as Bree, where the Hobbits meet Aragorn, or Rivendell, where the Fellowship is formed. It is part of the wider region of Eriador, but the question’s specific answer is the Shire.