| Sienno | |
| Settlement Type: | Village |
| Total Type: | |
| Subdivision Type: | Country |
| Subdivision Type1: | Voivodeship |
| Subdivision Name1: | Greater Poland |
| Subdivision Type2: | County |
| Subdivision Name2: | Słupca |
| Subdivision Type3: | Gmina |
| Subdivision Name3: | Ostrowite |
| Pushpin Map: | Poland |
| Coordinates: | 52.3833°N 18°W |
Sienno is a village in the administrative district of Gmina Ostrowite, within Słupca County, Greater Poland Voivodeship, in west-central Poland.[1] It lies approximately 4km (02miles) west of Ostrowite, 130NaN0 north-east of Słupca, and 740NaN0 east of the regional capital Poznań.