Getting an EIN for an Idaho Limited Partnership

The IRS assigns each Employer Identification Number as a nine-digit federal tax ID. It is the business equivalent of a Social Security number — the number that identifies your limited partnership to the federal government on tax filings, to banks when you open accounts, and to agencies when you hire or register.

Why a limited partnership always needs one

Unlike a single-member LLC, which can sometimes get by on the owner's Social Security number, a limited partnership always needs its own EIN. The reason is structural: a partnership files its own federal informational return (Form 1065) and issues a Schedule K-1 to each partner. That makes the partnership a distinct filer in the eyes of the IRS, and a distinct filer needs its own identifying number. There is no version of a properly run limited partnership that skips the EIN.

What you will use it for

• Filing the partnership's federal and Idaho returns
• Opening the partnership's bank account — banks require it
• Hiring employees and handling payroll tax
• Applying for business licenses or permits that ask for a federal tax ID
• Setting up state tax accounts, such as sales tax or withholding, if applicable

The application is quick, but it goes smoothly only if you have your details settled first. Applying before the partnership legally exists, or with inconsistent information, causes problems that are annoying to fix.

Form the partnership first

Get your Certificate of Limited Partnership on file with the Idaho Secretary of State before applying for the EIN, or at least have your final legal name and structure locked. The IRS ties the EIN to the partnership's legal name, so applying with a name that does not match your state filing creates a mismatch you will have to untangle later.

Gather this information

• The partnership's exact legal name as it appears on the Certificate of Limited Partnership, including the "LP" or "limited partnership" designator
• The partnership's address in Idaho
• The responsible party's name and taxpayer ID. The IRS requires a "responsible party" — a general partner (or an individual who controls the partnership) with a valid Social Security number or ITIN — for the online application
• The number of partners and the reason you are applying (starting a new business)
• The start date of the partnership and its accounting year

A note on the responsible party

The responsible party must be a natural person, not another entity, even if your general partner is an LLC or corporation. In that case, the IRS wants the individual who ultimately controls or manages the partnership, along with that person's SSN or ITIN. Have that person's information ready before you start.

The IRS issues EINs directly, at no cost. Be careful to use the official IRS process; third-party sites that charge a fee for something the IRS provides free are unnecessary.

The online method (fastest)

1. Go to the IRS EIN Assistant at IRS.gov and choose to apply for a new EIN.
2. Select "partnership" as the entity type — this is important, since the entity type affects how the IRS sets up the account.
3. Enter the responsible party's information (name and SSN or ITIN).
4. Enter the partnership's legal name, address, and details.
5. Submit. The EIN is issued immediately on screen, and you can download and print the confirmation notice to use the same day.

The online application is available during IRS operating hours and must be completed in one session — it times out after a period of inactivity, so have everything ready before you start. It also requires a responsible party with a U.S. SSN or ITIN.

If you have no SSN or ITIN

If the responsible party does not have a Social Security number or ITIN, you cannot use the online tool. Instead, complete IRS Form SS-4 and submit it by fax or mail. This route takes longer — days to weeks depending on method — but it is the standard path for partnerships with a foreign responsible party.

Getting the number is the start, not the end. A few things follow.

Store the confirmation safely

The IRS issues a confirmation notice (the CP 575 for mailed confirmations, or the printable letter online). Keep it with your partnership records — banks, the state, and your accountant may ask for it, and getting a replacement from the IRS is slower than saving the original.

Open the bank account

With the EIN in hand and your filed Certificate of Limited Partnership, you can open the partnership's bank account. Most banks want the EIN confirmation, the filed certificate, the limited partnership agreement, and ID for the authorized signers. Keeping partnership money in a dedicated account is essential for clean books and for the integrity of the structure.

Set up tax accounts

Use the EIN to register for any Idaho tax accounts you need — a seller's permit through the Idaho State Tax Commission if you will collect sales tax, withholding accounts if you will have employees, and so on. The EIN is the thread that ties the partnership's federal and state tax identities together.

Keep it consistent

Use the exact same legal name and EIN across every filing — federal returns, the Idaho partnership return, bank accounts, and licenses. Inconsistencies between how the partnership is named at the IRS, the state, and the bank are a frequent source of delays and rejected filings. Mainstay Filing focuses on getting your Idaho formation on file correctly; the EIN application itself is free and quick to do yourself directly with the IRS, and we are happy to point you to the right IRS resource.