IRS Office Mountainside

This page provides information about the IRS Office Mountainside location.

**NOTE that this TAC office may be closed. Visit the IRS site for alternate locations.**

IRS Office Mountainside – 200 Sheffield Street, Mountainside, NJ 07092

The Mountainside IRS Office is located in a building called Diamondhead Building, which is a commercial complex for offices mostly. Diamondhead is a city in Mississippi in Hancock County after which they named this building. However, this office is located close to highway 22 and houses a good number of offices. Nearby business locations are Union County Voice Magazine, Regency International Bus Corporation, Amal, Imagine – A Center for Coping with Loss, Walgreens District Office etc. Major tenants other than IRS on this property are Access to Money ATM Booth, Express Employment Professionals etc.


East on US-22: Head west on US-22 toward Magnolia Terrace. The exit toward Sheffield leads toward Mountain Avenue by turning right. Follow through this way, then take the ramp on the left to US-22 and merge onto Sheffield Street. The Diamondhead Building will be on the right.

West on I-78: Follow I-78 to County Road 527. Continue for a while, then take exit 45 from I-78. Continue on the embarked County Road and after a while take Baltusrol Pl and Summit Road to Sheffield Street in Mountainside. Drive until the Diamondhead Building is located.

North on Garden State Parkway: Drive on Garden State Parkway to Chestnut Street in Union. Take exit 139B from Garden State Parkway. Upon embarking, follow the Chestnut Street to US-22W. Drive until Mountain Avenue is reached and take exit toward Sheffield from US-22. Now, continue on Mountain Avenue and drive to Sheffield Street in Mountainside. Look for Diamondhead Building signs.

South on Garden State Parkway: Take Garden State Parkway and take exit 142B to Sheffield Street in Union County. Take a right turn onto Sheffield Street, the Diamondhead Building will be on the right on this street.


Monday through Friday 8.30 am to 4.30 pm. This office follows the federal holiday schedule.


Information: (908) 301-2112

Appointment: (844) 545-5640


Designated parking spaces in sufficient numbers (450 to be precise) surround this building, totaling in 3 acres of parking area.


All public visitors are required to walk through multiple stages of electronic security equipment. Presenting a government issued valid ID card is required to confirm identity and appointment.


All public visitors are required to take appointments prior to visiting, by calling the number provided above.


  • Account inquiries (help with letters, notices and levies on your wages or bank account)
  • Adjustments (changes to tax account information or payments)
  • Alien clearances (Sailing Permits)
  • Assistance with Affordable Care Act tax provision questions for individuals
  • Basic tax law assistance January 2 – April 18 (answers related to your individual Federal Tax Return) (Topics)
  • Check, money order, or cash payment acceptance (Exact Change is Required)
  • Form 911, Request for Taxpayer Advocate Service Assistance
  • Form 2290, Heavy Highway Vehicle Use Tax Return (submission of tax return if unable to e-file)
  • Individual Taxpayer Identification Numbers and Form W-7 (More Information)
  • Multilingual assistance (over 150 languages translated)
  • Payment arrangements
  • Procedural inquiries
  • Solutions to tax issues
  • Tax forms (based on availability)
Since information on our page might have changed, we recommend that you confirm office information at the IRS's office locator tool before visiting the IRS office.

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