| Onderwierum | |
| Settlement Type: | Hamlet |
| Pushpin Map: | Netherlands Groningen#Netherlands |
| Pushpin Mapsize: | 250 |
| Pushpin Map Caption: | Location in the province of Groningen in the Netherlands |
| Coordinates: | 53.3273°N 6.5807°W |
| Subdivision Type: | Country |
| Subdivision Name: |  Netherlands |
| Subdivision Type1: | Province |
| Subdivision Type2: | Municipality |
| Subdivision Name2: | Het Hogeland |
| Subdivision Type3: | Village |
| Subdivision Name3: | Onderdendam |
| Unit Pref: | Metric |
| Elevation Footnotes: | [1] |
| Elevation M: | 1.5 |
| Population Density Km2: | auto |
| Timezone1: | CET |
| Utc Offset1: | +1 |
| Timezone1 Dst: | CEST |
| Utc Offset1 Dst: | +2 |
| Postal Code Type: | Postcode |
| Postal Code: | 9959 |
| Area Code Type: | Area code |
| Area Code: | 050 |
Onderwierum is a hamlet in the municipality of Het Hogeland, in the province of Groningen. It is located just south of Onderdendam, of which it is a part administratively. The hamlet is built on two mounds and includes a former cemetery. The hamlet had its own church dating from the Middle Ages which was demolished in 1841.[2]
The old name of Onderwierum is Uldernawerum (charters in 1378 and 1386). The name has been reconstructed as Unlanderena wêr-hêm and is thus explained as a raised height (wierde) of people who lived in onland ("swamp"). The name of Onderdendam is also explained in this way.[3]