This beautiful thing. There is some loss along the lip on one side, but still, such an exquisite thing I think, and overall really beautifully preserved, late 19th or very early 20th century I believe. Imbrication--unique to Native American tribes of the lower Pacific Northwest and Cascades-Plateau regions, most notably from the Klickitat, Cowlitz, and Salish--is a decorative overlay technique on coiled baskets, created by catching strands of grass under select stiches, binding the added material to the exterior surface of the basket and then folding the decorative strand regularly back and forth on itself to create patterns on the outer surface of the basket. Baskets like this, and especially antique full imbricated examples like this, are quite precious.
I believe the materials here, based on others I have found with similar coloration and age, are cedar root, bear grass and cherry bark, and I believe this one is most likely Klickitat.
8 1/8" in diameter x 6 3/4" tall. See details for full documentation of condition--there is one obvious area of loss and one tiny split along the lip on the opposite side; otherwise the basket is in excellent condition, with a beautiful patina.