Terabithia is the magic land that Leslie and Jess create in the woods, a few yards from the dry creek bed that separates the farmland from the forest near their rural homes. The children, who are beset with the normal difficulties of family life and school, want a place "just for (them)...it would be so secret that (they) would never tell anyone in the whole world about it". Embellished by Leslie's vast imagination, Terabithia soon becomes "a whole secret country...and (she and Jess are ) the rulers of it".
Leslie patterns the goings-on of Terabithia after the "magic country of Narnia", from The Chronicles of Narnia by C.S. Lewis. From the books, she and Jess determine "how things (go) in a magic kingdom...how the animals and the trees must be protected and how a ruler must behave". The best thing about Terabithia is that there, Jess and Leslie are the rulers; they are in control. Their place as king and queen of the land is a welcome contrast for their real lives, where they often feel that they are at the mercy of everyone else's whims.
Terabithia is located in the woods, "where the dogwood and redbud (play) hide and seek between the oaks and evergreens, and the sun (flings) itself in golden streams through the trees to splash warmly at (the children's) feet". Leslie and Jess decide that, to get there, they must swing over the gully separating the area from the farmlands on a rope which someone had long ago hung from an old crab apple tree on the bank. Leslie and Jess build a "castle stronghold" in Terabithia by dragging boards and other materials over from a nearby scrap heap. When their stronghold is built, they stand back and examine it, and like God after He created the earth, they find it "very good". From Terabithia, "everything seem(s) possible...between the two of them they (own) the world and no enemy...could ever really defeat them" (Chapter 4).