Wash. Admin. Code § 220-300-220
When pertaining to angling, unless otherwise defined, any reference to the mouths of rivers or streams includes those waters of any river or stream, including sloughs and tributaries, upstream and inside of a line projected between the outermost uplands at the mouth. The term "outermost upland" means those lands not covered by water during an ordinary high tide. The following river mouths are hereby otherwise defined:
Abernathy Creek - Highway 4 Bridge.
Bear River - Highway 101 Bridge.
Bone River - Highway 101 Bridge.
California Creek - Drayton Harbor Road Bridge.
Chambers Creek - Burlington Northern Railroad Bridge.
Chehalis River - Highway 101 Bridge in Aberdeen.
Chelan River - Railroad Bridge.
Cispus River - Posted markers at the Lewis County P.U.D. kayak launch, approximately 1.5 miles upstream from the confluence of the Cowlitz and Cispus rivers.
Cowlitz River - A line projected across the river between two fishing boundary markers set on each bank of the river approximately one-half mile downstream from the lowermost railroad bridge crossing the Cowlitz River.
Dakota Creek - A line from the outermost headland of the south bank to a house at 1285 Runge Avenue, Blaine, Washington, approximately one-quarter mile downstream from the Blaine Road Bridge.
Deschutes River - A line projected across the river 400 feet below the lower Tumwater Falls fish ladder.
Drano Lake - Highway 14 Bridge.
Duwamish River - An east-west line extending through the southernmost tip of Harbor Island.
Elk River - Highway 105 Bridge.
Entiat River - Railroad Bridge.
Hawk Creek (Lincoln County) - Falls at the Hawk Creek campground.
Hoquiam River - Highway 101 Bridge.
Humptulips River - Mouth of Jessie Slough.
Johns River - Highway 105 Bridge.
Kalama River - Boundary markers at mouth.
Kennedy Creek - An arc 500 yards east of the midpoint of the northbound Highway 101 Bridge.
Kettle River - Barstow Bridge.
Klickitat River - Burlington Northern Railroad Bridge.
Lake Washington Ship Canal - A line 400 feet west of the fish ladder at the Chittenden Locks.
Lewis River - A straight line running from a fishing boundary marker or from the outermost upland at the north shore of the Lewis River mouth, southerly across the Lewis River to a fishing boundary marker near the south shore.
McLane Creek - A line 100 feet upstream of and parallel to the southernmost Highway 101 Bridge.
Minter Creek - A line from a point on the eastern most spit at the mouth of Minter Bay (47°21.49'N, -122°41.53'W) north to the opposite shore.
Methow River - Highway 97 Bridge.
Naselle River - Highway 101 Bridge.
North Nemah River - Highway 101 Bridge.
Niawiakum River - Highway 101 Bridge.
Nisqually River - At the upstream end of Alder Lake, the mouth of the Nisqually River is the Highway 7 Bridge at Elbe.
North River - Highway 105 Bridge.
Palix River - Highway 101 Bridge.
Puyallup River - 11th Street Bridge.
Samish River - The Samish Island Bridge (Bayview-Edison Road).
Sammamish River - 68th Avenue NE Bridge.
Skagit River - A line projected from the terminus of the jetty with McGlinn Island to the white monument on the easterly end of Ika Island, then to a white monument on the westerly end of Craft Island, then to a white monument near the corner of the levee on the westerly side of Dry Slough, and then to a white monument on the easterly side of Tom Moore Slough.
Skamokawa Creek - Highway 4 Bridge.
Skookum Creek - A line 400 yards below the old railroad bridge.
Snake River - Railroad bridge between Burbank and Pasco.
Snohomish River - Burlington Northern Railway Bridges crossing main river and sloughs.
South Nemah River - Lynn Point 117 degrees true to the opposite shore.
Spokane River - State Route 25 Bridge.
Tahuya River - North Shore Rd. Bridge.
Tucannon River - The water south of a line of sight from a sign with an orange triangle along the shoulder of Highway 261 (the northwest of the Tucannon River), southeast across to the eastern, unsubmerged shoreline of the Tucannon River. (The embayment between the eastern shoreline of the Tucannon River and the rock bluff to the east that has an affixed orange channel navigation marker, along the south shore of the Snake River, is considered part of the Snake River.)
Wallace River - The furthest downstream railroad bridge.
Washougal River - A straight line from the Crown Zellerbach pumphouse southeasterly across the Washougal River to the east end of the Highway 14 Bridge near the upper end of Lady Island.
Whatcom Creek - A line projected approximately 14 degrees true from the flashing light at the southwesterly end of the Port of Bellingham North Terminal to the southernmost point of the dike surrounding the Georgia Pacific treatment pond.
Little White Salmon River - At boundary markers on river bank downstream from the Little White Salmon National Fish Hatchery.
White Salmon River - Burlington Northern Railroad Bridge.
Willapa River - City of South Bend boat launch.
Wind River - Boundary line markers at mouth.
Yakima River - Highway 240 Bridge.
Wash. Admin. Code § 220-300-220