| Place Name | Alto |
| Place Type | Census Designated Place |
| ZIP Code(s) | 94941 |
| County | Marin County |
| Area Code(s) | 415,628 |
| Timezone | Pacific Daylight Time (PDT) |
| Population (2022) | 745 |
| Population Growth Rate (2010-19) | 2.95% |
| Majority Ethnicity | White 84.98% |
| Metro/Micro Stats Area | San Francisco-Oakland-Berkeley, CA |
| US Congressional District(s) | California 2nd |
| State Assembly Districts | 10 |
| State Senate Districts | 2 |
| Race/Ethnicy | Percentage of Population (2021) |
|---|---|
| White | 84.98% |
| African American | 2% |
| Hispanic | 0% |
| Asian | 1.68% |
| Native American | 0% |
| Hawaiin/Pacific Islander | 11.34% |