Location: SD-20 and Tie Creek Rd, Harding Cty Reassurance shield as SD-20 begins. The highway heads north up the state line for about a mile. Location: SD-20 and Little Missouri Rd, Harding Cty As we turn off the state line into South Dakota, we get the full welcome treatment. Given how bad the road from … Continue reading South Dakota Highway 20, MT S-328 to US-85