Though based in the "written Torah" of the Bible (Tanach), Halacha itself is further elaborated upon by the "oral Torah," which was written down as the Mishna and Talmud.
Later rabbinic works greatly expanded on Halacha, most famously the Shulchan Aruch, written in Safed by Rabbi Yosef Karo in the 16th century, which, along with the commentaries on it, is widely considered the most authoritative work on Halacha.
