| Caption: | Standard South Dakota state highway shields |
| Statehwy: | (State) Highway X (SD X) |
| Interstate: | Interstate X (I-X) |
| Us: | U.S. Highway X (US X) |
| Notes: | South Dakota highways are generally state-maintained. |
| Links: | SD |
South Dakota's state highways were assigned in a numbering pattern that followed that of the U.S. Highways followed upon their inception. East–west highways carried even numbers and increased from North to South – while north–south highways carried odd numbers and increased from east to west. This holds true only for two-digit highways. Three-digit highways follow the odd–even routing, but do not sequentially remain near a "parent" route as a spur or alternate route, instead being more independent of any parent two-digit route.