S.D. Codified Laws § 55-3-6 (2026)
Unless the terms of a trust expressly reserve a power to the settlor to revoke or modify a trust, a trust shall be irrevocable.
Source: SDC 1939, § 59.0216; SL 1993, ch 355 , § 2; SL 1998, ch 282 , § 9; SL 2019, ch 209 , § 5.