Short answer
A principal office address is the address of a company’s main executive office. Washington law defines a principal office as “the principal executive office of an entity, whether or not the office is located in this state.” Colorado and Washington say it cannot be a PO Box, and Washington also says a PMB cannot be used. Oregon says it may not be a PO Box, a commercial mail receiving agency, a mail forwarding business, or a virtual office.
Key takeaways
- Washington law (RCW 23.95.105) says “Principal office” means “the principal executive office of an entity, whether or not the office is located in this state.” Virginia law uses similar words and adds “in or out of the Commonwealth.”
- Colorado’s Articles of Organization help page says the principal office street address “must be a physical address and cannot be a post office box.” A separate principal office mailing address is optional.
- Washington’s Secretary of State says the Principal Office address “must be the street address of the business” and that “A PO BOX or PMB cannot be used for the physical address requirement but can be provided as an alternate mailing address.”
- Oregon’s form instructions say “The principal office may not be a PO Box, a commercial mail receiving agency, a mail forwarding business, or a virtual office.”
- The principal office is a different address from the registered office, where the registered agent accepts legal papers. It is also different from the IRS “principal place of business” test for the home office deduction.
What is a principal office address?
A principal office address is the address of the company’s main office. Washington and Virginia law describe it as the principal executive office, which is the place where the people who run the company do that work. You give this address to the Secretary of State when you form an LLC or a corporation, and some states, such as Washington, ask for it again on annual reports.
Forms do not all use the same words. You may see “principal office,” “principal address,” or “principal office street address.” The label changes from state to state. The question behind it is the same: where is the company’s main office?
This guide explains the general idea across states. If your LLC is in Florida, our guide to the Sunbiz principal address and mailing address covers Florida’s two fields. For Georgia, see our guide to the principal office address on the Georgia annual registration.
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How state law defines a principal office
Washington defines the term in RCW 23.95.105, a section that applies to many kinds of business entities. Subsection (28) reads: “‘Principal office’ means the principal executive office of an entity, whether or not the office is located in this state.” The words “whether or not the office is located in this state” mean the principal office can be in another state or another country.
Virginia’s Limited Liability Company Act uses a longer definition in Section 13.1-1002. It says “Principal office” means “the office, in or out of the Commonwealth, where the principal executive offices of a domestic or foreign limited liability company are located or, if there are no such offices, the office, in or out of the Commonwealth, so designated by the limited liability company.” The second half covers a company with no executive office. In that case, the LLC chooses which office counts.
Virginia also says what the articles of organization must include. Section 13.1-1011 lists “The post office address, including the street and number, if any, of the principal office of the limited liability company, which may be the same as the registered office, but need not be within the Commonwealth.” So in Virginia, the principal office and the registered office may share one address. The principal office also does not have to be in Virginia.
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How Colorado, Washington, and Oregon word the field
The statute tells you what a principal office is. The form instructions tell you what the state will accept in the box. The three states below each add their own limits. The table quotes the key words of each instruction.
Colorado splits the field in two. Its help page for the online Articles of Organization says “A principal office street address is required. The street address must be a physical address and cannot be a post office box.” The second field is the principal office mailing address. The page says “A mailing address is optional. If the mailing address is different than the street address, or mail cannot be delivered to the street address, provide the address, including the city, state and ZIP/postal code where mail is to be delivered.” The page’s example for the mailing field is a PO Box in Lakewood, Colorado.
Washington’s Secretary of State cites RCW 23.95.105(28) and says: “The Principal Office address must be the street address of the business. A PO BOX or PMB cannot be used for the physical address requirement but can be provided as an alternate mailing address.” PMB means private mailbox. The page adds that the address “can be the same as the Registered Agent, or it can be a separate location where records are maintained.” Since January 20, 2026, Washington also requires an email address in the principal office section of originations and annual reports.
Oregon’s instructions for the Articles of Organization are the strictest of the three. They say “The principal office may not be a PO Box, a commercial mail receiving agency, a mail forwarding business, or a virtual office.” Oregon’s form has a separate field called “Address where the Division may mail notices.” The instructions say it is “An address where renewal notices will be mailed. Other types of mail will also be delivered to this publicly available address.” The instructions for that field do not list any address types it refuses.
| State | Field name | What the state’s instructions say |
|---|---|---|
| Colorado | Principal office street address | “The street address must be a physical address and cannot be a post office box.” |
| Colorado | Principal office mailing address | “A mailing address is optional.” Give it if it differs from the street address or “mail cannot be delivered to the street address.” |
| Washington | Principal Office | “must be the street address of the business. A PO BOX or PMB cannot be used for the physical address requirement but can be provided as an alternate mailing address.” |
| Oregon | Principal office | “may not be a PO Box, a commercial mail receiving agency, a mail forwarding business, or a virtual office.” |
| Oregon | Address where the Division may mail notices | “An address where renewal notices will be mailed. Other types of mail will also be delivered to this publicly available address.” |
Principal office address vs registered office
The registered office is the address of your registered agent, the person or company that accepts legal papers for the LLC. Oregon’s instructions describe it as an “Oregon street address” that “must be suitable for personal delivery of legal papers to the Registered Agent.” The Washington and Virginia definitions say the principal office can be in or out of the state.
The two addresses can sometimes be the same. Virginia’s statute says the principal office “may be the same as the registered office.” Washington says its principal office address “can be the same as the Registered Agent.” Our guide to the registered agent address and the business address explains the registered agent side in more detail.
The principal office can also receive legal papers in some cases. Colorado’s registered agent FAQ says that if the registered agent “cannot be physically located and personally served,” the entity may be served “by registered mail or by certified mail, return receipt requested, addressed to the entity at its principal address.” The FAQ cites Section 7-90-704(2) of the Colorado Revised Statutes. So someone should read mail sent to the principal office.
Principal office vs the IRS principal place of business
The IRS uses a similar phrase for a different purpose. In Publication 587, Business Use of Your Home, “principal place of business” is one of the tests for the home office deduction. The publication says “To qualify to deduct the expenses for the business use of your home under the principal place of business test, your home must be your principal place of business for that trade or business.”
Publication 587 explains how to decide. It says you must consider “The relative importance of the activities performed at each place where you conduct business” and “The amount of time spent at each place where you conduct business.” That test is about a tax deduction. It is not a rule for what you write in the principal office field of a state form, and the state forms above do not refer to it.
Who can see your principal office address
Plan on the principal office address being public. Washington’s Secretary of State says “All information provided to the Secretary of State is considered public record and available to anyone.” Oregon calls its notice address a “publicly available address.” Colorado’s FAQ says that when a foreign entity withdraws and chooses not to keep a registered agent, “correspondence will be delivered to the principal office address on file.”
If you run the business from home, the address you list may be your home address. Before you file, read the exact words on your state’s form. Check whether the form asks for a street address, whether it refuses a PO Box, and whether it names other address types it will not take. Oregon’s list of refused address types is longer than Colorado’s or Washington’s. If a form does not say, ask the Secretary of State’s office before you file.
Some states also have a separate mailing address field. Colorado’s is optional, and Washington says a PO Box or PMB “can be provided as an alternate mailing address.” Read your own state’s words for that field before you fill it in. For general business mail, our Los Angeles business address and Silicon Valley virtual office address pages describe the business addresses save office offers.
Not legal or tax advice
This guide summarizes Washington RCW 23.95.105, Virginia Code Sections 13.1-1002 and 13.1-1011, the Colorado, Washington, and Oregon Secretary of State pages, and IRS Publication 587 cited here, as read on October 31, 2026. Form instructions change. Check your state’s current form, and ask an attorney or tax professional about your own company.
Frequently Asked Questions
Sources & References
Primary sources this guide is based on.
- 1Washington State Legislature · RCW 23.95.105 Definitions (accessed October 31, 2026)
- 2Virginia General Assembly · Code of Virginia Section 13.1-1002 Definitions (accessed October 31, 2026)
- 3Virginia General Assembly · Code of Virginia Section 13.1-1011 Articles of organization (accessed October 31, 2026)
- 4Colorado Secretary of State · Articles of Organization help (accessed October 31, 2026)
- 5Colorado Secretary of State · Registered agent FAQs (accessed October 31, 2026)
- 6Washington Secretary of State · Contact Info Requirements and Updates (accessed October 31, 2026)
- 7Oregon Secretary of State · Articles of Organization Form Instructions (accessed October 31, 2026)
- 8Internal Revenue Service · Publication 587, Business Use of Your Home (accessed October 31, 2026)
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