Tualatin Valley
The valley is formed by the meandering Tualatin River , a tributary of the Willamette River at the northwest corner of the Willamette Valley , east of the Northern Oregon Coast Range . 
<triplet> Tualatin River <subj> Willamette River <obj> mouth of the watercourse <triplet> Willamette River <subj> Tualatin River <obj> tributary <triplet> Willamette Valley <subj> Willamette River <obj> located in or next to body of water