Submitting SS-4 by Mail: Match the Route to the Applicant’s Location

The practical answer

The right mailing route depends on the applicant's circumstances and the current instructions, not on whichever address is easiest to find online. An application review should connect the applicant's location facts with the specific submission route being selected. Three details shape the review: Which applicant-location facts control this route? Is the mailing instruction current and applicable? Does the addressed package match that instruction? Keep each answer tied to the document or confirmed fact that supports it.^{[1] [2, p.6] [3, p.1] [2, p.3]}

Scope and the records behind the answer

The discussion follows the entity, form and transaction conditions identified below. The same label on a different form can have a different purpose. Keep the relevant entity and reporting period visible while you compare the requirements, and treat each stated exception as part of the rule rather than an optional footnote.

Official sources checked: 2026-11-09. Annual tax-year forms and continuously revised forms are identified separately in the references.

A side-by-side preparation table

Work through the official requirements

Ein international submission routes

The IRS EIN page gives phone, fax and mail routes for applicants whose principal place of business is outside the United States.^[1]

This applies when: Scope is principal place of business, not citizenship alone; recheck current recipient details before submission.

Ein domestic fax mail routes

For a U.S. principal place of business, the IRS EIN page lists online, fax and mail routes and warns that inventory levels can delay processing.^[1]

This applies when: Online-tool eligibility has its own requirements; IRS estimates are not a company delivery promise.

Authorized signer

The authorized SS-4 signer depends on the type of applicant. A foreign applicant may use a person with appropriate authorization to sign.^{[2, p.6]}

Field/section 4a: Mailing address (room, apt., suite no. and street, or P.O. box)

Enter the mailing address for IRS correspondence, including room, suite and other applicable address details.^{[3, p.1] [2, p.3]}

Field/section 4b: City, state, and ZIP code (if foreign, see instructions)

For a foreign address, include the city, province or state, postal code and full country name. Do not abbreviate the country name.^{[3, p.1] [2, p.3]}

Field/section 6: County and state where principal business is located

Identify the entity's principal physical business location. A mailing address does not automatically become its business location.^{[3, p.1] [2, p.3]}

Designee scope

The third-party designee may answer questions about the completed SS-4 and receive the new EIN. Signed authorization is required, and that authority ends when the EIN is assigned and released to the designee.^{[2, p.6]}

Not entity election

Checking an entity-type box on SS-4 is not itself an entity-classification tax election.^{[2, p.4]}

Ein confirmation 147c

The current IRS EIN page lists requesting Letter147C through its business and specialty tax line as a way to confirm an existing EIN.^[1]

This applies when: No promise that a preparation service can bypass disclosure or authentication rules.

An illustrative preparation scenario

In this hypothetical preparation example, an owner forwards a mailing address from an old checklist while the current application contains a different location profile. The preparer compares those circumstances with the applicable SS-4 instructions, keeps the addressed copy in the file, and records what remains to be checked before mailing. The preparer checks three points: Which applicant-location facts control this route? Is the mailing instruction current and applicable? Does the addressed package match that instruction? The file remains a working comparison until the relevant facts and applicable instructions have been checked together. No agency outcome is assumed.^{[1] [2, p.6] [3, p.1] [2, p.3]}

This is a planning illustration, not a statement that a particular filing has been accepted or that an entity qualifies for a tax result. Use the source-backed distinctions above to decide what information still needs to be established before a form is completed.

A review sequence you can actually use

1. Which applicant-location facts control this route?
2. Is the mailing instruction current and applicable?
3. Does the addressed package match that instruction?

Write down the answer and the record that supports it, rather than marking a question complete because a field contains text. When two records disagree, identify whether the difference concerns the entity, an individual, the reporting period or the type of change. That makes the remaining question specific enough to resolve against the relevant instruction.

Keep the scope of a preparation service separate from the government requirement. A service intake question may gather information for a workflow; it does not create an exception, extend a deadline or determine whether a transaction is reportable. The cited government material remains the basis for those conclusions.

Questions to settle before moving forward

How should I check authorized signer?

The authorized SS-4 signer depends on the type of applicant. A foreign applicant may use a person with appropriate authorization to sign. ^{[2, p.6]}

How should I check field/section 4a: mailing address (room, apt., suite no. and street, or p.o. box)?

Enter the mailing address for IRS correspondence, including room, suite and other applicable address details. ^{[3, p.1] [2, p.3]}

How should I check field/section 4b: city, state, and zip code (if foreign, see instructions)?

For a foreign address, include the city, province or state, postal code and full country name. Do not abbreviate the country name. ^{[3, p.1] [2, p.3]}

How should I check field/section 6: county and state where principal business is located?

Identify the entity's principal physical business location. A mailing address does not automatically become its business location. ^{[3, p.1] [2, p.3]}

Official sources and versions

1. Employer identification number
2. Instructions for Form SS-4 (Rev. December 2025) — Rev. December 2025
3. Form SS-4 (Rev. December 2025) — Rev. December 2025

Get help with the relevant SpeedEIN workflow

SpeedEIN offers preparation and support for the situations described on its service pages. If you would like assistance, review the relevant service scope, supported entities and current availability before ordering. The service does not replace the government’s decision or remove an obligation imposed by the applicable rules.

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