How to Get an EIN in South Dakota (2026)

Fact-checked by the LegalGlass editorial team against primary sources · Published Aug 6, 2026 · Last updated Aug 6, 2026

To get an Employer Identification Number (EIN) in South Dakota, apply directly with the Internal Revenue Service (IRS) for free. The fastest method is the IRS online application, which provides the EIN immediately. South Dakota has no state income tax, but most businesses, including LLCs and corporations, still need an EIN for federal tax purposes, opening business bank accounts, and registering for a South Dakota sales tax license with the Department of Revenue.

What is an EIN and Why Do South Dakota Businesses Need One?

An Employer Identification Number (EIN), also known as a Federal Tax Identification Number, is a unique nine-digit number assigned by the IRS to identify businesses for tax purposes. It functions like a Social Security Number (SSN) for a business entity. Most South Dakota businesses will need an EIN, regardless of their legal structure (e.g., South Dakota LLC, corporation, partnership).

Key reasons a South Dakota business needs an EIN include:

• Federal Tax Filings: Required for filing federal income tax returns, employment tax returns (if you have employees), and other IRS forms.
• Hiring Employees: Essential for any business that pays wages to employees.
• Opening a Business Bank Account: Banks typically require an EIN to open a business checking or savings account.
• Sales Tax License: The South Dakota Department of Revenue uses the EIN when you apply for a sales tax license or other state tax licenses.
• Forming Certain Entity Types: All corporations and partnerships must have an EIN. Multi-member LLCs also require an EIN.
• Electing S-Corporation Status: If an LLC or corporation elects to be taxed as an S-corporation, an EIN is necessary.

Even though South Dakota has no state income tax, an EIN is still central to federal tax administration. A single-member LLC treated as a disregarded entity generally uses the owner's SSN, but if it elects corporate taxation or has employees, an EIN becomes mandatory. For a comprehensive overview, see how to get an EIN.

When is an EIN Required for a South Dakota Business?

The IRS provides specific criteria for when an EIN is required. For South Dakota businesses, an EIN is generally necessary if the business:

• Has employees.
• Operates as a corporation or partnership.
• Files any of these tax returns: Employment, Excise, or Alcohol, Tobacco, and Firearms.
• Withholds taxes on income, other than wages, paid to a non-resident alien.
• Has a Keogh plan.
• Is involved with certain organizations, such as trusts, estates, real estate mortgage investment conduits, non-profit organizations, farmers' cooperatives, or plan administrators.
• Is a multi-member Limited Liability Company (LLC).
• Is a single-member LLC that elects to be taxed as a corporation (including S-corporation).

A single-member LLC in South Dakota treated as a disregarded entity and without employees typically does not need an EIN and can use the owner's SSN for federal tax purposes. However, many banks and the South Dakota Department of Revenue may still request an EIN, making it practical to obtain one even if not strictly required by the IRS. For more details, consult the IRS guidance on Do You Need an EIN?

How to Apply for an EIN in South Dakota (Step-by-Step)

Applying for an EIN is a free process conducted directly with the IRS. There are four main methods, with the online application being the fastest. Before applying, ensure your South Dakota business entity has been officially formed with the South Dakota Secretary of State (for example, by filing Articles of Organization for an LLC or Articles of Incorporation for a corporation).

1. Gather Necessary Information

Before you begin the application, you will need the following information:

• Responsible Party's Taxpayer Identification Number (TIN): A valid Social Security Number (SSN), Individual Taxpayer Identification Number (ITIN), or an existing EIN. The responsible party is the individual or entity that ultimately owns or controls the entity or exercises ultimate effective control over it. For online applications, the responsible party must have a U.S. TIN.
• Business Name and Address: The legal name of your South Dakota business as registered with the Secretary of State, and its mailing address.
• Type of Entity: Whether your business is an LLC, corporation, partnership, sole proprietorship, etc.
• Reason for Applying: Common reasons include "Started new business," "Hired employees," or "Banking purposes."
• Date Business Started: The month and year your South Dakota business began operations.

2. Choose Your Application Method

The IRS offers several ways to apply for an EIN:

Online Application (Recommended)

This is the fastest method. The IRS online application is available during specific hours (typically Monday to Friday, 7 a.m. to 10 p.m. Eastern Time). You receive your EIN immediately upon successful completion. The responsible party must have a valid U.S. TIN (SSN, ITIN, or existing EIN). Only one EIN can be requested per responsible party per day. Access the IRS Online EIN Application.

Fax Application

Complete Form SS-4, Application for Employer Identification Number. Fax the completed form to the IRS. If you provide a return fax number, you can expect to receive your EIN back within approximately four business days. Confirm the current fax numbers on the IRS website before sending.

Mail Application

Complete Form SS-4 and mail it to the IRS. This is the slowest method, with processing times typically ranging from several weeks. The IRS lists the correct mailing address for domestic applicants on its "Where to File Your Taxes (for Form SS-4)" page.

Telephone Application (International Applicants Only)

International applicants who do not have a U.S. TIN can apply for an EIN by calling 267-941-1099 (not a toll-free number). This service is available Monday to Friday during posted hours. An assistant completes Form SS-4 with you over the phone, and you receive your EIN immediately.

After Getting Your EIN: South Dakota State Requirements

Once you have your EIN, your South Dakota business will use it for federal tax purposes and for state licensing. A key point for South Dakota is that the state imposes no individual or corporate income tax, so there is no state income tax return to file. State business obligations run primarily through the South Dakota Department of Revenue for sales and use taxes.

• Sales Tax License: Businesses selling taxable goods or services in South Dakota must obtain a sales tax license from the Department of Revenue before making sales. Your EIN is used on the tax license application. See our overview of South Dakota sales tax.
• Use Tax: Use tax applies to items used in South Dakota on which sales tax was not paid. The Department of Revenue administers this alongside sales tax, and the EIN identifies your account.
• Federal Employment Taxes: If your business has employees, your EIN is used for federal payroll tax deposits and returns, even though there is no state income tax withholding in South Dakota.
• Entity Registration: Formation and annual reports for LLCs and corporations are filed separately with the South Dakota Secretary of State, which is distinct from tax licensing with the Department of Revenue.

It is crucial to keep your EIN secure and use it consistently across all federal and state filings. For more on registering, review the South Dakota sales and use tax information and our South Dakota business license overview.

Common EIN Application Issues and Solutions

While applying for an EIN is generally straightforward, some common issues can arise:

• Responsible Party Requirements: For online applications, the responsible party must have a U.S. SSN, ITIN, or existing EIN. If not, you must apply by fax or mail, or by phone if you are an international applicant. See what is an ITIN.
• Duplicate EIN Request: If you already have an EIN, you generally do not need a new one unless there is a significant change in your business structure (for example, a sole proprietorship incorporates). The IRS limits one EIN per responsible party per day online.
• Incorrect Business Name: Ensure the business name on your EIN application exactly matches the name registered with the South Dakota Secretary of State. Discrepancies can cause issues with banks and the Department of Revenue.
• Application Errors: Double-check all information before submitting. Errors can lead to delays or incorrect EIN assignments.
• Lost EIN: If you lose your EIN, you can find it on previous tax returns, IRS notices, or by contacting the IRS directly. The IRS does not re-issue EINs.

If you encounter difficulties, the IRS website provides extensive FAQs and contact information. For state-level questions about your sales tax license, contact the South Dakota Department of Revenue.

Frequently Asked Questions

How do I get an EIN for my South Dakota LLC?

Apply for an EIN directly with the IRS. The fastest way is online through the IRS website, which provides the EIN immediately upon completion. You can also apply by fax or mail using Form SS-4.

Is an EIN free in South Dakota?

Yes, an EIN is always free when obtained directly from the Internal Revenue Service (IRS). There are no state or federal fees for an EIN.

Does South Dakota have a state income tax?

No. South Dakota does not impose a state individual or corporate income tax. However, businesses selling taxable goods or services must register for a South Dakota sales tax license, and an EIN is still required for federal purposes.

Does a single-member LLC in South Dakota need an EIN?

A single-member LLC in South Dakota treated as a disregarded entity by the IRS generally does not need an EIN unless it has employees or elects corporate taxation. Otherwise, it may use the owner's Social Security Number (SSN).

What do I need to apply for an EIN in South Dakota?

You need a valid Taxpayer Identification Number (SSN, ITIN, or another EIN) for the responsible party, the business name and address, and the type of entity. For online applications, the responsible party must have a U.S. TIN.

How long does it take to get an EIN for a South Dakota business?

If you apply online through the IRS website, you receive your EIN immediately after completing the application. Fax applications typically take about four business days, and mail applications can take several weeks.

Related

• How to get an EIN (cluster hub)
• How to form an LLC in South Dakota
• South Dakota registered agent requirements
• South Dakota business license requirements
• How to get an EIN in Delaware (sibling)
• How to get an EIN in Mississippi (sibling)
• What is an ITIN?
• Business tax overview
• South Dakota sales tax
• S-Corp vs. LLC

Sources

1. IRS - Employer ID Numbers (General information on EINs).
2. IRS - How to Apply for an EIN (Overview of application methods).
3. IRS - Do You Need an EIN? (Criteria for EIN requirement).
4. IRS - About Form SS-4, Application for Employer Identification Number (Details on the application form).
5. IRS - Apply for an Employer Identification Number (EIN) Online (Online application and hours).
6. IRS - Applying for an EIN by Fax (Fax numbers and processing times).
7. IRS - Applying for an EIN by Mail (Mailing addresses and processing times).
8. IRS - Taxpayer Identification Numbers (TIN) (Information on SSN, ITIN, EIN).
9. IRS - Limited Liability Company (LLC) (Federal tax treatment of LLCs).
10. IRS - S Corporations (Information on S-corp election).
11. South Dakota Secretary of State - Business Services (South Dakota entity formation and filings).
12. South Dakota Department of Revenue - Business Taxes (State tax administration).
13. South Dakota Department of Revenue - Sales & Use Tax (Sales tax license requirement).
14. South Dakota Department of Revenue - Tax License Application (Applying for a sales tax license).
15. Cornell Law School Legal Information Institute - Employer Identification Number (EIN) (Legal definition and context).

LegalGlass provides general information for educational purposes and is not a law firm or a substitute for advice from a licensed attorney or tax professional. Laws, fees, and thresholds change; verify current requirements with the IRS and the South Dakota Department of Revenue before acting.