| Business | Phone |
| Horizons Counseling & Ed Center 124 W Main St, Smithtown 11787 | (631) 360-7578 |
| Smithtown Animal Shelter 410 E Main St, Smithtown 11787 | (631) 360-7575 |
| Smithtown Building Dept 99 W Main St, Smithtown 11787 | (631) 360-7520 |
| Smithtown Community Planning 2 Redwood Ln, Smithtown 11787 | (631) 360-7587 |
| Smithtown Crisis Intervention 124 W Main St, Smithtown 11787 | (631) 360-7581 |
| Smithtown Crisis Intervention 7 New York Ave, Smithtown 11787 | (631) 360-7581 |
| Smithtown Engineering 124 W Main St, Smithtown 11787 | (631) 360-7550 |
| Smithtown Engineering 99 W Main St, Smithtown 11787 | (631) 360-7550 |
| Smithtown Parent Resource Center 7 New York Ave, Smithtown 11787 | (631) 360-7517 |
| Smithtown Personnel 65 Maple Ave, Smithtown 11787 | (631) 360-7626 |
| Smithtown Planning Comm Dev 99 W Main St, Smithtown 11787 | (631) 360-7540 |
| Smithtown Purchasing 99 W Main St, Smithtown 11787 | (631) 360-7630 |
| Smithtown Receiver Of Taxes 99 W Main St, Smithtown 11787 | (631) 360-7610 |
| Smithtown Senior Citizens Center 420 E Main St, Smithtown 11787 | (631) 360-7676 |
| Smithtown Supervisor's Office 99 W Main St, Smithtown 11787 | (631) 360-7600 |
| Smithtown Town Board Office 99 W Main St, Smithtown 11787 | (631) 360-7621 |
| Smithtown Traffic Safety Dept 758 Smithtown Byp, Smithtown 11787 | (631) 360-7635 |
| Smithtown Youth Bureau 7 New York Ave, Smithtown 11787 | (631) 360-7595 |
| Village Of The Branch Hall 40 Route 111, Smithtown 11787 | (631) 265-3315 |