S.D. Codified Laws § 10-21-7.2
Any remittance transmitted electronically pursuant to § 10-21-7.1 shall be made on or before the first day of the month and are considered to have been made on the date that the remittance is credited to the bank account designated by the treasurer. For purposes of making any electronic transfer of remittance pursuant to §§ 10-21-7.1 to 10-21-7.3, inclusive, the first day of the month means the first day of the month, unless the first day of the month is a Saturday, Sunday, a legal holiday enumerated in § 1-5-1, or a day which the Federal Reserve Bank is closed, then the electronic transfer of remittance is due on the next succeeding day that is not a Saturday, Sunday, a legal holiday enumerated in § 1-5-1, or a day which the Federal Reserve Bank is closed.
SDCL 10-21-7.2