Abstract: The Sonoran Preserve Plant Inventory Project is a partnership between the Conservation Alliance, the Plant Atlas Project of Arizona and the City of Phoenix Parks and Recreation Department. The overarching goal of the project is to document the floristic diversity of Sonoran Preserve for scientific, land management, educational, and conservation purposes. The preserve includes two major “islands” approximately bounded by I-17 to the west, Carefree Highway to the north, Cave Creek Road to the east, and Happy Valley Road to the south. A third island is north of Carefree Highway at Tramonto and is bounded by Skunk Creek to the west. The primary plant community in Sonoran Preserve is Arizona Uplands and associated seasonal riparian communities. The area includes portions of four major washes: Cave Creek, Apache Wash, Skunk Creek and Bobcat Wash, plus minor tributaries. The washes drain desert hills with exposed bedrock of granite, basalt and metamorphic rocks. Elevations range from ~450-746 meters (1500-2450 feet). Many people assisted in specimen collection and identification for this project, including: Jackie Anderson, Cass Blodgett, Dawn Goldman, Jim Griffith, Debi Quarry and Kris Schloemer.