The Samish River originates on a low divide in Whatcom County, and its tributary, Friday Creek, originates in the hills south of Bellingham. The river continues its southwesterly flow through Skagit County and outlets into Samish Bay in Puget Sound.
The Samish River and its tributary, Friday Creek, both originate from low elevations in Whatcom County and hills near Bellingham, respectively. Both flow southwest into Samish Bay within Puget Sound.