SDCL § 9-3-1.1: Minimum distance from existing municipality--Exceptions.

A municipality may not be incorporated if any part of the proposed municipality lies within three miles of any point on the perimeter of the corporate limits of an incorporated municipality, unless:

(1) The incorporated municipality refuses or fails to annex a territory that is contiguous to the incorporated municipality after the contiguous territory has properly petitioned the municipality to be annexed as provided by § 9-4-1; or

(2) The territory to be incorporated has a post office and:

(a) Is in a different county than the incorporated municipality; or

(b) The incorporated municipality has a population of less than five thousand.