This dataset describes Tribal Lands in Washington State. Included are areas where the tribes ceded title to their historic areas of use to the U.S. Government through various treaties enacted during the later half of the 19th century. Boundary lines have been digitized from a variety of digital data sources including 1:100,000 streams for boundaries described in treaties as following a stream or river, 1:24k Water Resource Inventory Areas (WRIA), Watershed Administrative Unit (WAU) and Hydrologic Unit Code (HUC) boundaries for boundaries referred to in treaties as 'divide', 'summit' or 'between the waters of', 1:100,000 Major Public Lands (for current reservation areas), 10 meter DEM and 7.5 minute USGS digital Quad maps (to define ridgelines and 'divide' where WRIA, WAU or HUC boundaries don't exist) and NAIP orthophoto imagery (to get a feel for what a questionable boundary area actually looks like today). Ceded Land treaty areas are based on treaty language and US Government decrees dated 1854-1892. Natural geographic barriers such as streams and ridge lines were used where described or eluded to in treaty descriptions. Coordinate based latitude/longitude boundary lines were used in some Central Washington areas where described. References to general compass directions were followed using natural barriers such as watershed boundaries or drainages wherever possible. Some treaty boundary descriptions were found to be inadequate, inaccurate and in some cases misleading in nature in describing what should have been a natural boundary or even a coordinate based solution to a property description. Some of these boundary areas open to interpretation are discussed below in the Supplemental Information based on the language and definite boundaries of other treaty areas. Ceded areas in Oregon and Idaho from the Camp Stevens Treaties have been included in this dataset. The Washington State Department of Ecology makes no warranty for the accuracy of this material and is not libel for its use. Ecology will maintain this data layer for its own use and distribute to all interested parties. Updates, corrections and documentation should be submitted to the contact person. This data may or may not reflect the most current tribal reservation areas. Tribal reservations are updated regularly in the Major Public Lands (MPL) layer maintained by Washington State Department of Natural Resources. This GIS data is draft information and a work in progress and should be used only as a generalized visual guide to 150 year old treaties of limited content.