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Step-by-step guide · Illinois

3 Best Foreign Registration Services in Illinois (2026), Ranked for You

In Illinois for 2026, compare Illinois Registered Agent.co ($199), IL Registered Agent.org ($199) and Mainstay Filing ($199), ranked best first. Plan on $150 for the state and $397 to $497 in service fees across three years.
Written by the Simple Filing Guide editorial team

Quick guide

What you pay the state
$150
Paper from your home state?
Yes, it is required (60 days old at the most)
Ongoing
$75, annual report
First choices
Illinois Registered Agent.co, IL Registered Agent.org then Mainstay Filing

Our Illinois shortlist

The order follows our five checks: three-year cost first, then what the price covers.

#1 Recommended first

1. Illinois Registered Agent.co: best for one extra state

Pay $199 to register and $99 for the agent after

Start with Illinois Registered Agent.co in Illinois: the fee is $199 with the first year of agent service included, then $99 annually.

Compare the three-year totals: it lands under Mainstay Filing, and cost is the check we weigh most.

Checklist: what is included
  • Illinois registration filing
  • A year of agent service to start
What works
  • Adds $199 to the state fee
  • $99 a year from year two
  • Year one of the agent comes with it
Gaps
  • Single-state coverage
Go to Illinois Registered Agent.co Partner link. We may earn money if you buy.
#2 Illinois specialist

2. IL Registered Agent.org: best for a second in-state filer

Pay $199 to register and $99 for the agent after

Next, consider IL Registered Agent.org: the fee is $199 with the first year of agent service included, then $99 annually.

It charges the same as Illinois Registered Agent.co, so the order between them is a close call.

Checklist: what is included
  • Illinois registration filing
  • A year of agent service to start
What works
  • $99 a year from year two
  • Year one of the agent comes with it
  • Adds $199 to the state fee
Gaps
  • Single-state coverage
Go to IL Registered Agent.org Partner link. We may earn money if you buy.
#3 All fifty states

3. Mainstay Filing: best for companies that keep growing

Pay $199 to register and $149 for the agent after

Next, consider Mainstay Filing: it charges $199 plus state fees and waives the registered agent the first year.

At $100 above Illinois Registered Agent.co over three years, it sits lower in the ranking.

There is no registered agent fee in year one; from year two it is $149 a year.

Checklist: what is included
  • State registration done for you
  • Registered agent, no charge in the first year
  • Priced identically in any state
What works
  • Adds $199 to the state fee
  • Year-one agent service included
  • One fee for any state
Gaps
  • Renewal lands $50 over Illinois Registered Agent.co
Go to Mainstay Filing Partner link. We may earn money if you buy.

The table

#ProviderYear-one costYearly afterThree-year costWhat is covered
1 Illinois Registered Agent.co $199$99/yr$397illinois registration filing; A year of agent service to start Go to Illinois Registered Agent.co Partner link. We may earn money if you buy.
2 IL Registered Agent.org $199$99/yr$397illinois registration filing; A year of agent service to start Go to IL Registered Agent.org Partner link. We may earn money if you buy.
3 Mainstay Filing $199$149/yr$497state registration done for you; registered agent, no charge in the first year; priced identically in any state Go to Mainstay Filing Partner link. We may earn money if you buy.

Company prices from November 13, 2026, before state fees.

The key questions

Is my LLC obliged to register here?

Register with the Illinois Secretary of State, Department of Business Services, Limited Liability Division before your LLC does business in Illinois.

Doing business unregistered risks it cannot sue in Illinois courts until it registers (805 ILCS 180/45-45(a)); fees owed for the gap before registering.

verify at ilga.gov, as of October 2026

How much does registration cost?

$150 to the state, $199 to a service.

Across three years the state's total comes to $300. verify at ilsos.gov, as of October 2026

Which form do I file, and with whom?

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

The filing needs certificate of Good Standing or Existence issued in the past 60 days.

Are there ongoing fees to plan for?

The state wants a annual report later, priced at $75.

Filings come due Within the 60 days before your anniversary month.

Why is the list in this order?

Illinois Registered Agent.co leads on total for three years, which carries 37% of our score.

The two heavy checks are total for three years (37%) and filing jobs included (27%); three lighter checks follow.

Compare the totals: Illinois Registered Agent.co runs $397 for three years, $100 below Mainstay Filing.

The five checks

Illinois registration checklist

StepWhat to knowWhere it is from
Application fee $150verify at ilsos.gov, as of October 2026
Certificate from your home state Yes, it is required, 60 daysverify at ilga.gov, as of October 2026
Annual report $75verify at ilga.gov, as of October 2026
What the state collects in three years $300Our sum of the rows above

Last row = filing fee + report in year two + report in year three + minimum tax, if any. Variable costs are described in the text, not added.

Quick answers

Will one agent cover both states?

Most likely yes. One national provider is able to manage your home state and this one together.

What do the picks cost over three years?

Three-year costs: Illinois Registered Agent.co, $397; IL Registered Agent.org, $397; Mainstay Filing, $497, not counting state fees.

What sources do you use?

Every state fee links to its official page, and every service price is read from the company's own site.

Do I have to use a service?

Hiring is optional. The law requires a filing, not a filer.

Is filing part of the service?

Yes. Every pick prepares and files it, and the state fee is the same whichever you choose.

Who ranks first in Illinois?

Illinois Registered Agent.co is on top because its service fees come to $397 across three years; IL Registered Agent.org and Mainstay Filing follow.

Where each fact comes from

  1. Illinois Secretary of State, Department: confirmed August 2026 using ilsos.gov
  2. Illinois Secretary of State, Department: confirmed August 2026 using ilsos.gov
  3. 805 ILCS 180/5-5: confirmed August 2026 using ilga.gov
  4. Illinois formation fee: Filing fee: confirmed October 2026 using ilga.gov
  5. Illinois formation fee: Filing fee: confirmed October 2026 using ilsos.gov
  6. Illinois registered agent statute: confirmed October 2026 using ilga.gov
  7. Form LLC-45.5, Application for Admission: confirmed October 2026 using ilsos.gov
  8. Form LLC-45.40, Application for Withdrawal: confirmed October 2026 using ilsos.gov
  9. 805 ILCS 180/45-45, consequences of: confirmed October 2026 using ilga.gov
  10. 805 ILCS 180/45-47, activities that: confirmed October 2026 using ilga.gov
  11. 805 ILCS 180/45-45: confirmed November 2026 using ilga.gov
  12. Pricing from the Illinois Registered Agent.co pricing page, November 13, 2026
  13. Pricing from the IL Registered Agent.org pricing page, November 13, 2026
  14. Pricing from the Mainstay Filing Illinois service page, November 13, 2026