| Official Name: | Upper Greenwood Lake, New Jersey |
| Settlement Type: | Census-designated place |
| Pushpin Map: | USA New Jersey Passaic County#USA New Jersey Sussex County#USA New Jersey#USA |
| Pushpin Label: | Upper Greenwood Lake |
| Pushpin Map Caption: | Location in Passaic County##Location in Sussex County##Location in New Jersey##Location in the United States |
| Pushpin Relief: | yes |
| Pushpin Label Position: | bottom |
| Coordinates: | 41.1833°N -74.38°W |
| Subdivision Type: | Country |
| Subdivision Name: |  United States |
| Subdivision Type1: | State |
| Subdivision Type2: | County |
| Subdivision Name2: | Passaic, Sussex |
| Subdivision Type3: | Townships |
| Subdivision Name3: | West Milford Vernon |
| Area Footnotes: | [1] |
| Area Total Sq Mi: | 3.16 |
| Area Land Sq Mi: | 2.74 |
| Area Water Sq Mi: | 0.42 |
| Area Total Km2: | 8.19 |
| Area Land Km2: | 7.09 |
| Area Water Km2: | 1.09 |
| Population As Of: | 2020 |
| Population Density Km2: | 519.72 |
| Timezone: | Eastern (EST) |
| Utc Offset: | −05:00 |
| Timezone Dst: | EDT |
| Utc Offset Dst: | −04:00 |
| Elevation Ft: | 1110 |
| Postal Code Type: | ZIP Code |
| Postal Code: | 07421 (Hewitt) |
| Area Code: | 973/862 |
| Blank Name: | FIPS code |
| Blank Info: | [2] |
| Blank1 Name: | GNIS feature ID |
| Blank1 Info: | 2806211 |
| Population Total: | 3687 |
| Unit Pref: | Imperial |
| Population Density Sq Mi: | 1346.11 |
Upper Greenwood Lake is a census-designated place (CDP)[3] in Passaic and Sussex counties, in the U.S. state of New Jersey. It includes residential neighborhoods around the northern and central parts of its namesake lake. It is primarily in West Milford Township in Passaic County but extends to the northwest into Vernon Township in Sussex County. It is bordered to the west by Wawayanda State Park, to the southeast by Abram S. Hewitt State Forest, and to the northeast by the town of Warwick in Orange County, New York.
The lake drains to the northeast into Long House Creek, which descends into New York and joins Wawayanda Creek, a west-flowing tributary of Pochuck Creek, which in turn runs north to the Wallkill River, a northeast-flowing tributary of the Hudson.
The Upper Greenwood Lake community was first listed as a CDP prior to the 2020 census.
The respective school districts are West Milford Township Public Schools for sections in West Milford Township, Passaic County;[4] and Vernon Township School District for sections in Vernon Township, Sussex County.[5]