| Holtwood, Pennsylvania | |
| Settlement Type: | Unincorporated community |
| Pushpin Map: | Pennsylvania#USA |
| Pushpin Label: | Holtwood |
| Subdivision Type: | Country |
| Subdivision Name: | United States |
| Subdivision Type1: | State |
| Subdivision Name1: | Pennsylvania |
| Subdivision Type2: | County |
| Subdivision Name2: | Lancaster |
| Subdivision Type3: | Township |
| Subdivision Name3: | Martic |
| Unit Pref: | Imperial |
| Area Total Km2: | 1.86 |
| Area Land Km2: | 1.85 |
| Area Water Km2: | .01 |
| Population As Of: | 2000 |
| Population Total: | 97 |
| Population Density Km2: | auto |
| Timezone: | Eastern (EST) |
| Utc Offset: | -5 |
| Timezone Dst: | EDT |
| Utc Offset Dst: | -4 |
| Coordinates: | 39.8319°N -76.3275°W |
| Postal Code Type: | ZIP code |
| Postal Code: | 17532 |
| Blank Name: | FIPS code |
| Blank1 Name: | GNIS feature ID |
| Blank1 Info: | 1177240 |
Holtwood is an unincorporated community in Martic Township, Lancaster County, in the U.S. state of Pennsylvania.
Holtwood is the site of the Muddy Run Pumped Storage Hydroelectric Power Plant (172 Bethesda Church Road West, Holtwood, PA 17532), along the Susquehanna River. It pumps water into a reservoir during off-peak hours and uses that water to generate electricity during peak demand hours; it produces over 1,000 megawatts (MW) of power.[1]