There isn't a single "first BTC contract address" because Bitcoin's early days involved simple transactions, not complex smart contracts; however, the first-ever Bitcoin address, linked to Satoshi Nakamoto for receiving funds (1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa), Satoshi nakamoto wallet 1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa