S.D. Codified Laws § 29A-5-418
Within ninety days following an appointment, a conservator shall file and record a certified copy of the letters of conservatorship in the office of the register of deeds in the county of appointment and in any county in which the minor or protected person owns real estate. A conservator may, but need not, file and record the letters in other counties, and a guardian may, but need not, record the letters of guardianship in any county. A filing shall include an affidavit that designates the real estate owned by the minor or protected person and which contains a legal description. The filing and recording of a certified copy of the letters is constructive notice of the existence of the guardianship or conservatorship until the same is discharged by the like filing and recording of a certified copy of an order terminating the guardianship or conservatorship.
SDCL 29A-5-418