| Official Name: | Underhill Flats, Vermont |
| Settlement Type: | Census-designated place |
| Pushpin Map: | Vermont#USA |
| Pushpin Label: | Underhill Flats |
| Coordinates: | 44.5258°N -72.945°W |
| Subdivision Type: | Country |
| Subdivision Name: | United States |
| Subdivision Type1: | State |
| Subdivision Name1: | Vermont |
| Subdivision Type2: | County |
| Subdivision Name2: | Chittenden |
| Subdivision Type3: | Towns |
| Subdivision Name3: | Underhill Jericho |
| Area Footnotes: | [1] |
| Area Total Km2: | 1.94 |
| Area Land Km2: | 1.94 |
| Area Water Km2: | 0.0 |
| Population As Of: | 2020 |
| Timezone: | Eastern (EST) |
| Utc Offset: | -5 |
| Timezone Dst: | EDT |
| Utc Offset Dst: | -4 |
| Elevation Ft: | 705 |
| Postal Code Type: | ZIP Codes |
| Postal Code: | 05489 (Underhill) 05465 (Jericho) |
| Area Code: | 802 |
| Blank Name: | FIPS code |
| Blank Info: | 50-74125 |
| Blank1 Name: | GNIS feature ID |
| Blank1 Info: | 2807140 |
Underhill Flats is an unincorporated village and census-designated place (CDP) in the towns of Underhill and Jericho, Chittenden County, Vermont, United States. It was first listed as a CDP prior to the 2020 census.
The CDP is in northeastern Chittenden County, in the western part of the town of Underhill and the northern part of the town of Jericho. It sits in the valley of The Creek where it flows into the Browns River, which forms the southern border of the CDP. The Browns River is a west- and north-flowing tributary of the Lamoille River, in turn a tributary of Lake Champlain.
Vermont Route 15 passes through Underhill Flats, leading north 11miles to Cambridge and southwest 3miles to Jericho. Underhill Center is to the southeast via River Road, and Burlington, the state's largest city, is to the west-southwest.