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Researched and written by the Launchwise Review editorial team
Launchwise Review

Rankings of registered agents, LLC formation and foreign registration services in all 50 states.

Launch guide · Illinois · foreign registration

3 Best Foreign Registration Services in Illinois (2026)

Researched and written by the Launchwise Review editorial team
For a 2026 launch in Illinois, Launchwise Review grades foreign registration services this way: Mainstay Filing ($199), Illinois Registered Agent.co ($199) and IL Registered Agent.org ($199). Mainstay Filing earns the top grade here: $199 on top of the state fee, a free first year as registered agent and the same price in any state.
1
Top pick on this page

1. Mainstay Filing: best for founders working in several states

Pay $199 plus the state fee ($349 in total at checkout), then $149 a year for the agent

Our mark 9.4 out of 10

Top grade, Mainstay Filing: the Illinois registration costs $199, the first registered agent year is free, and later years are $149.

Your first year as agent is free; each year after that is $149, wherever you register.

It runs $100 above Illinois Registered Agent.co across three years; the extra paperwork it handles is worth that to us.

In the price

  • The registration filing, done for you
  • The first registered agent year at no charge
  • Anything served on the company scanned the same business day at no fee

Pros

  • $199 for the service, with the state fee added
  • One price in every state
  • Registered agent service is free the first year
  • Papers served on the company are scanned the same business day, free

Less good

  • The agent costs $149 a year after year one, $50 above Illinois Registered Agent.co
Visit Mainstay FilingPartner link. We may earn money if you buy.
Read the Mainstay Filing launch review
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Lower renewal than Mainstay

2. Illinois Registered Agent.co: best for companies adding only Illinois

Service $199, state fee extra; the agent then costs $99 each year

Our mark 9.2 out of 10

Next up is Illinois Registered Agent.co: $199 beyond the state fee gets the company into Illinois, with the agent renewing at $99.

You get an in-state street address for the registered office, and any papers served on the company are scanned into your online account.

In the price

  • Illinois registration filed for you
  • One year of registered agent service to begin with

Pros

  • Keeps your agent for $99 yearly
  • Covers the first year of registered agent service
  • $199 covers the registration work, fees extra

Less good

  • Illinois only; the home state needs its own agent
  • EIN application costs extra ($99)
Visit Illinois Registered Agent.coPartner link. We may earn money if you buy.
Read the Illinois Registered Agent.co launch review
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Best local option

3. IL Registered Agent.org: best for Illinois registrations only

Service $199, state fee extra; the agent then costs $99 each year

Our mark 9.0 out of 10

Rounding out the list is IL Registered Agent.org: $199 beyond the state fee gets the company into Illinois, with the agent renewing at $99.

You get an in-state street address for the registered office, and any papers served on the company are scanned into your online account.

IL Registered Agent.org copies Illinois Registered Agent.co on price and features, so the pair is close to level.

In the price

  • Illinois registration filed for you
  • A first year as your registered agent

Pros

  • Free registered agent service in year one
  • $199 to register, plus the state fee
  • Then $99 a year to keep the agent

Less good

  • Illinois only; the home state needs its own agent
  • EIN application costs extra ($99)
Visit IL Registered Agent.orgPartner link. We may earn money if you buy.
Read the IL Registered Agent.org launch review

The 3 grades at a glance

Place Company Launch grade Service price Second year Best fit Go
1 Mainstay Filing 9.4 $199 $149/yr Founders opening a second state Visit Mainstay FilingPartner link. We may earn money if you buy.
2 Illinois Registered Agent.co 9.2 $199 $99/yr The lowest agent renewal on this page Visit Illinois Registered Agent.coPartner link. We may earn money if you buy.
3 IL Registered Agent.org 9.0 $199 $99/yr The lowest agent renewal on this page Visit IL Registered Agent.orgPartner link. We may earn money if you buy.
The 10-point grades are editorial, built from the criteria on How we rank. They are not customer ratings.

Illinois foreign registration service cost in 2026: first year, renewals, three-year total

Company Year 1 Year 2 Year 3 Three years, total Agent covered, year one
Mainstay Filing $199 $149 $149 $497 Free
Illinois Registered Agent.co $199 $99 $99 $397 Included
IL Registered Agent.org $199 $99 $99 $397 Included
Prices were copied from each company's own pages on November 12, 2026. Add Illinois's $150 registration fee to any row; it is not in the totals.

What drove the grades

What made the call in Illinois was launch paperwork handled. The grading method sets cost to launch and stay at 26%, launch paperwork handled at 26% and renewal behavior, state match and price transparency at 48% combined.

Adding a second state means dealing with two states, and one provider at one price in both earned the stronger coverage grade, ahead of Illinois Registered Agent.co.

Every criterion and weight is listed on How we rank.

Opening in Illinois as a foreign LLC: fee, form and office

Your registration goes to the Illinois Secretary of State, Department of Business Services, Limited Liability Division, on the Application for Admission to Transact Business (Form LLC-45.5). Budget $150 for the state. Have certificate of Good Standing or Existence in hand too, dated within 60 days of filing; Illinois asks for it.

Calendar item for later: the annual report at $75, due within the 60 days before your anniversary month.

Before you file, get these together

  • Certificate of Good Standing or Existence, issued within 60 days of your filing date.
  • Your company's exact legal name and the date it was formed at home.
  • A registered agent with a street address in the state; every company graded on this page can serve.
  • The $150 state fee, ready to pay with the filing.
  • A calendar reminder for the annual report and its $75 fee.

What skipping Illinois registration can cost you

Without registration, an outside LLC cannot bring a lawsuit in Illinois courts (805 ILCS 180/45-45(a)). Contracts it signs remain valid (805 ILCS 180/45-45(b)). Back fees for the unregistered months are due as well.

Quick answers about Illinois foreign registration services

When does an LLC from elsewhere have to register in Illinois?

Once it does business there. Until then it cannot bring a lawsuit in the state's courts.

What should I budget to bring an existing LLC into Illinois?

The state fee is $150; add a service fee of $199.

Which form brings a foreign LLC into Illinois?

Ask the Illinois Secretary of State, Department of Business Services, Limited Liability Division for the Application for Admission to Transact Business (Form LLC-45.5).

Do I need a document from my home state first?

Yes, order certificate of Good Standing or Existence and file within 60 days of its date.

Does the foreign LLC still need a registered agent?

Yes. Keep a registered agent with a street address in the state for as long as the company is registered there.

Which service is the best way to register a foreign LLC in Illinois?

Mainstay Filing, because $199 beyond the state's fee in whichever state you enter, with year-one registered agent service free.

Read next

Sources and dates

  1. Illinois Secretary of State, Department of Business Services, Limited Liability Division, dated August 2026
  2. Illinois Secretary of State, Department of Business Services, Limited Liability Division, dated August 2026
  3. 805 ILCS 180/5-5, dated August 2026
  4. Illinois formation fee: Filing fee, official source, dated October 2026
  5. Illinois formation fee: Filing fee, official source, dated October 2026
  6. Illinois registered agent statute, dated October 2026
  7. Form LLC-45.5, Application for Admission, dated October 2026
  8. Form LLC-45.40, Application for Withdrawal, dated October 2026
  9. 805 ILCS 180/45-45, consequences of transacting business without admission, dated October 2026
  10. 805 ILCS 180/45-47, activities that are not transacting business, dated October 2026
  11. 805 ILCS 180/45-45, dated November 2026
  12. From Mainstay Filing: Illinois service page, copied November 12, 2026
  13. From Illinois Registered Agent.co: pricing and service pages, copied November 12, 2026
  14. From IL Registered Agent.org: pricing and service pages, copied November 12, 2026