| Official Name: | Fairfield Township, Buena Vista County |
| Settlement Type: | Township |
| Subdivision Type: | Country |
| Subdivision Type1: | State |
| Subdivision Type2: | County |
| Subdivision Name2: | Buena Vista |
| Area Total Km2: | 94.95 |
| Area Land Km2: | 94.95 |
| Area Water Km2: | 0 |
| Unit Pref: | Imperial |
| Area Total Sq Mi: | 36.66 |
| Area Land Sq Mi: | 36.66 |
| Area Water Sq Mi: | 0 |
| Population As Of: | 2000 |
| Population Total: | 951 |
| Population Density Km2: | 10 |
| Population Density Sq Mi: | 25.9 |
| Elevation Footnotes: | [1] |
| Elevation M: | 397 |
| Elevation Ft: | 1302 |
| Coordinates: | 42.7789°N -94.9722°W |
| Blank Name: | FIPS code |
| Blank Info: | 19-91272[2] |
| Blank1 Name: | GNIS feature ID |
| Blank1 Info: | 0467808 |
Fairfield Township is one of eighteen townships in Buena Vista County, Iowa, USA. As of the 2000 census, its population was 951.
Fairfield Township covers an area of 36.66sqmi and contains one incorporated settlement, Albert City. According to the USGS, it contains two cemeteries: Fairfield and Smith.