Based on the squash blossom form of his necklace (a Navajo adaptation of the crescent-shaped "naja" of the Spanish, from what I understand), I belief the chief represented here is most likely Southwestern Pueblo, and I would guess the watercolor dates to the early 20th century. I love his face, and the soft, relatively subtle palette and manner of the painting, which makes it feels pretty tender to me.

11 1/4" x 9 1/4" framed. Visible image: 8 1/2" x 6 1/2". Very good condition, with light scattered stains, in the nice old wooden frame I found it in.