Colorado drainage basins Table of major drainage basins Major Drainage Basins of the State of Colorado

| Basin | Outlet | Total_Area | In_State_Area | _In_State |
|---|---|---|---|---|
| Two Butte Creek | Arkansas River | 056 2,107km 2 814mi 2 | 046 2,107km 2 814mi 2 | A021 100% |
| Mancos River | San Juan River | 057 2,099km 2 810mi 2 | 047 1,973km 2 762mi 2 | A033 94.0% |
| Conejos River | Rio Grande | 058 2,078km 2 802mi 2 | 056 1,471km 2 568mi 2 | A044 70.8% |
| North Fork Smoky Hill River | Smoky Hill River | 059 1,965km 2 759mi 2 | 064 947km 2 366mi 2 | A050 48.2% |
| Sidney Draw | South Platte River | 060 1,949km 2 753mi 2 | 070 368km 2 142mi 2 | A061 18.9% |
| South Fork Beaver Creek | Beaver Creek | 061 1,939km 2 749mi 2 | 068 522km 2 201mi 2 | A055 26.9% |