area but has a slightly smaller flow. The Sacramento, when combined with the Pit, is also one of the longest rivers in the United States entirely within one state—after Alaska's Kuskokwim and Texas' Trinity. The major drainage basins bordering that of the Sacramento are that of the Klamath in the north, the San Joaquin and Mokelumne to the south and the Eel River in the west. The Russian River also lies to the west and the endorheic (closed) Honey Lake and Eagle Lake basins to the north. On the east side are many endorheic watersheds of the Great Basin including the Truckee River and Carson River. Parts of the Sacramento watershed come very close to, but do not extend past, the border of California and Nevada. Physiography The basin's diverse geography ranges from the glacier-carved, snowcapped peaks of the Sierra Nevada to the sea-level (and often lower) marshes and farmlands of the Sacramento-San Joaquin Delta. The highest point is at Mount Shasta, a dormant stratovolcano near the headwaters of the Sacramento River. The Sierra Nevada peaks generally decrease in height from south to north—from over in the headwaters of the American River near Lake Tahoe, to in Lassen County where they adjoin the Cascade Range. On the west side, the Coast Ranges are the opposite, increasing in height to almost in the north. The arid volcanic plateaus in the northeast, which are characterized by alternating hills and large sedimentary basins, typically lie at elevations of . Most of the Sacramento Valley is below in elevation; in its lower course, the Sacramento River drops only about per mile. Between the bajadas or alluvial slopes extending from the foothills of the Sierra Nevada and Coast Ranges, are the low floodplains of the Sacramento River. The river flows at an elevation somewhat higher than the surrounding terrain due to deposits of sediment over millennia that created raised banks (essentially natural levees). The banks separate the river from the lowlands to the east and west that once served as vast overflow basins during winter storms, creating large areas of seasonal wetlands. Since the 19th century, artificial levee systems have been constructed to enable farming in the fertile flood plain. Today there are of irrigated farmland in the Sacramento Valley. Due to the reduction of the floodplain area, the speed of flood flow in the Sacramento River has increased, creating a significant hazard for the