Indian Motorcycles Sturgis/Eagle Rider - watching Lazelle Street (2106 Lazelle) streaming
KOTA Territory News (Loud American Roadhouse) - watching Main and 3rd Street in downtown Sturgis (1305 Main) streaming
The South Dakota DOT has two webcams that focus on I90.
These are not live streaming but they do refresh fairly quickly.
View looking east toward Sturgis
View looking west toward Sturgis