10 and SD 45 curve back to the east. Approximately later, they enter Leola. SD 45 splits off to the south onto Mason Street. This intersection is also the southern terminus of CR 19 (363rd Avenue). SD 10 continues to the east and, at an intersection with 373rd Avenue, enters the northwestern part of Brown County. Brown County SD 10 travels just north of Willow Creek Lake and crosses over Elm River before it intersects US 281 (386th Avenue) southwest of Barnard. The two highways travel concurrently to the north, while the roadway continues as 115th Street. At an intersection with 112th Street, SD 10 splits off to the east. It passes the Sand Lake National Wildlife Refuge and crosses over Sand Lake before traveling through Houghton. The highway curves to the north onto 403rd Avenue and then back to the east onto 110th Street. At 404th Avenue, it intersects SD 37. The two highways travel concurrently to the east for approximately , splitting at 406th Avenue. SD 10 continues its eastward path. At an intersection with the southern terminus of 412th Avenue, the highway enters the west-central part of Marshall County. Marshall County SD 10 travels through West Britton before entering Britton. At Main Street, SD 27 begins a concurrency with SD 10. They cross over some railroad tracks of BNSF Railway. At an intersection with the northern terminus of 429th Avenue, SD 27 splits to the north. Then, SD 10 curves to the southeast and then travels through an area that has a lot of lakes. It travels just south of Sixmile Lake and then just south of Cottonwood Lake. Just south-southeast of the appropriately-named Lake City, the highway begins a concurrency with SD 25. This concurrency is just under . SD 10 continues to the southeast, just northeast of Clear Lake. It then slips between North Red Iron Lake and South Red Iron Lake. The highway curves back to the east and enters the northwestern part of Roberts County. Roberts County SD 10 continues in a relatively eastward direction and enters Sisseton. It travels just north of the Coteau des Prairies Hospital and then crosses over some railroad tracks of BNSF Railway. Just before leaving the city limits of Sisseton, SD 10 meets the southern terminus of SD 127 (459th Avenue). The highway travels just south of the Sisseton Municipal Airport just before an interchange with I-29/US