S.D. Codified Laws § 7-27-16
Associations or nonprofit operating corporations may be formed to serve on behalf of any county or two or more counties jointly for the purpose of holding and conducting annual fairs or exhibitions to promote and encourage agriculture, horticulture, stock-raising, and general domestic industries and for the purpose of disseminating information with respect to agriculture, horticulture, stock-raising, and general domestic industries or any one of them. Any nonprofit operating corporation having a lease or working agreement with any county as provided by § 7-27-11 may contract with additional counties, so long as all such counties are adjacent to each other and form a compact area, for purposes of conducting a joint fair.
The secretary of such association or nonprofit operating corporation shall file a copy of its articles of association or incorporation, as the case may be, with the county auditors of the counties joined in such enterprise and shall annually file a list of officers for that year and a report of all receipts and expenditures not later than December thirty-first of each year with the said county auditors of each such county. One member of the board of county commissioners of each joining county shall be appointed to serve ex officio on the board of directors of the association or corporation, as the case may be.
SDCL 7-27-16