| Municipalities | Mercer Area District |
| County | Municipality | County | Municipality | County | Municipality | |||
| Mercer | East Windsor Township | Mercer | Lawrence Township | Mercer | West Windsor Township | |||
| Mercer | Ewing Township | Mercer | Pennington Borough | Middlesex: | Cranbury Township | |||
| Mercer | Hamilton Townshp | Mercer | Princeton Borough | Middlesex: | Plainsboro Township | |||
| Mercer | Hightstown Borough | Mercer | Princeton Township | Somerset: | Montgomery Township | |||
| Mercer | Hopewell Borough | Middlesex: | Robbinsville Township | Somerset: | Rocky Hill Borough | |||
| Mercer | Hopewell Township | Middlesex: | Princeton Township | |||||
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Please note that Princeton Borough will be merged into Princeton Township on Jan-01-2013. |
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