S.D. Codified Laws § 31-12A-26
Notwithstanding any other provision of this chapter, a road district may contract for and expend district funds for road work projects to be constructed outside of the geographical area of the road district, if the board of trustees approves that action by a two-thirds vote of the membership. The owners of any land, including any land subject to an easement, outside the district on which the road is to be constructed shall consent in writing to the project. If persons outside the district area would also benefit from such a project, the board may negotiate with and accept funds or any other assistance from any person on the basis and terms negotiated. The provisions of § 31-12A-25.1 do not apply to any road work performed pursuant to this section.
SDCL 31-12A-26