Like its smaller, more familiar form, a basin is a land form that collects the water that runs into it. A watershed is a term used to describe an area of land that drains downward to its lowest point.
The USGS number found next to the watershed names refer to hierarchy of watershed types, each with its own Hydrologic Unit Code (HUC) identification numbers. The number 17120003, for example, denotes the Donner und Blitzen watershed and is referred to as a "4th field HUC". These types of watersheds are quite large, and they can be further subdivided into smaller or 5th field HUCs.
The watersheds listed here are 4th field watersheds that intersect the boundaries of the Lakes Basin.