The castle that administered the Wieliczka salt mine stands above the town, separate from the mine entrance but an integral part of the same centuries-long operation. Built in the 14th century and expanded through the Renaissance, it was the seat of the Żupy Krakowskie — the royal salt administration — and the residence of the mine's chief administrator.
Today it houses the Salt Museum, which tells the history of the Wieliczka mine, the salt trade, and the technology of underground salt extraction from medieval to modern times. The collections include mining tools, documents, maps, and models of the various levels of the mine at different periods. It complements the underground tour well, giving the administrative and historical context that the mine itself cannot easily convey.