There are several possible definitions of the extent of the Black Rock Desert. Often people refer just to the playa surface. Sometimes terrain which can be seen from the playa is included. The widest definition of the Black Rock Desert region is the watershed of the basin that drains into the playa. The intermittent Quinn River is the largest river in the region, starting in the Santa Rosa Range and ending in the Quinn River Sink on the playa south of the Black Rock Range. The watershed covers including the Upper and Lower Quinn River, Smoke Creek Desert, Massacre Lake, and Thousand Creek/Virgin Valley watersheds of northwestern Nevada as well as small parts across the borders of California and Oregon.