| Mount Hannah | |
| Coordinates: | 38.8873°N -122.7463°W |
| Map: | USA California |
| Country: | United States |
| State: | California |
| State Type: | State |
| District: | Lake County |
| District Type: | County |
| Type: | Lava dome |
| Volcanic Region: | Clear Lake volcanic field |
Mount Hannah is a mountain in the Mayacamas Mountains of the Northern California Coast Ranges.It is in Lake County, California.
Mount Hannah is in Lake County, California.It is one of the mountains in the Cobb Mountain Area, many of which have volcanic origin.Others are Cobb Mountain, the most dominant, Seigler Mountain and Boggs Mountain.There are isolated small valleys and basins between the mountain peaks.
Mount Hannah has an elevation of .Clean prominence is .Isolation is .The nearest higher neighbor is Cobb Mountain to the south.
Mount Hannah formed quite quickly during a polarity transition.It was built up by a number of closely-spaced eruptions.Three of the dacites in the Mount Hannah sequence have been dated to between 0.90 and 0.92 million years ago.There are indications that there may be a crustal magma chamber about 10- in diameter and a depth of below Mount Hannah, with a temperature above .