| Official Name: | Fjärdhundra |
| Pushpin Map: | Sweden Uppsala#Sweden |
| Subdivision Type: | Country |
| Subdivision Name: | Sweden |
| Subdivision Type3: | Municipality |
| Subdivision Name3: | Enköping Municipality |
| Subdivision Type2: | County |
| Subdivision Name2: | Uppsala County |
| Subdivision Type1: | Province |
| Subdivision Name1: | Uppland |
| Area Footnotes: | [1] |
| Area Total Km2: | 1.08 |
| Population As Of: | 31 December 2020 |
| Population Footnotes: | [2] |
| Population Total: | 932 |
| Population Density Km2: | auto |
| Timezone: | CET |
| Utc Offset: | +1 |
| Timezone Dst: | CEST |
| Utc Offset Dst: | +2 |
| Coordinates: | 59.7772°N 16.9264°W |
Fjärdhundra is a locality situated in Enköping Municipality, Uppsala County, Sweden with 951 inhabitants in 2010.
The name was given to a railway station in 1906, taken from the region Fjärdhundraland, which means land of the four hundreds, where in Sweden hundred meant an area having one hundred trained soldiers or shipsmen.