A river that flows for 425 miles (685 km) from the Rocky Mountains in Colorado through Denver and across Colorado to Nebraska, where it joins the North Platte River to form the Platte River.
Definition of South Platte River in US English:
South Platte River
proper noun
A river that flows for 425 miles (685 km) from the Rocky Mountains in Colorado through Denver and across Colorado to Nebraska, where it joins the North Platte River to form the Platte River.