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The Formation Desk

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

Foreign registration picks · Illinois

3 Best Foreign Registration Services in Illinois (2026)

The The Formation Desk call for foreign registration services in Illinois in 2026: Illinois Registered Agent.co ($199), Mainstay Filing ($199) and IL Registered Agent.org ($199), in that order. Illinois Registered Agent.co takes the call: the Illinois registration for $199, first agent year included, then $99 yearly.
Written by The Formation Desk editorial team
1
Number one here

1. Illinois Registered Agent.co: best for adding only Illinois

A $199 service fee plus state fees, then $99 a year for the agent

Editorial score 9.6 out of 10

The desk picks Illinois Registered Agent.co: $199 over the state fee to register in Illinois, agent renewing at $99.

You get an in-state street address as the registered office, and papers served there are scanned into your account.

Its three-year bill sits under Mainstay Filing's, which counts heavily in our method.

In the price

  • Foreign registration done for you
  • The first year as your registered agent

Strengths

  • Registration at $199 before state fees
  • Registered agent service for year one is covered
  • $99 yearly to keep the agent

Cons

  • Illinois only; your home state needs its own agent
  • EIN application will cost you $99 more
Visit Illinois Registered Agent.coPartner link. We may earn money if you buy. Illinois Registered Agent.co up close
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Best for expanding companies

2. Mainstay Filing: best for companies working in more than one state

$199 for the service, $349 due at checkout with the state fee; agent $149 a year after year one

Editorial score 9.1 out of 10

Runner-up, Mainstay Filing: it files the Illinois registration for $199 and serves as your registered agent, free in year one, then $149 a year.

Agent service costs nothing in year one and $149 a year from then on, whichever state you register in.

Illinois Registered Agent.co undercuts Mainstay Filing by $100 over three years, and that is why Mainstay sits lower on cost.

In the price

  • Registration paperwork prepared and filed
  • Registered agent service costs nothing in year one
  • Papers served on the company scanned and uploaded on the same business day, free

Strengths

  • Registered agent costs nothing in year one
  • $199 service fee, state fee on top
  • Free scans of served papers on the same business day
  • Same price in all fifty states

Cons

  • Agent renewal of $149 is $50 above Illinois Registered Agent.co
Visit Mainstay FilingPartner link. We may earn money if you buy. Mainstay Filing up close
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Low renewal

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

A $199 service fee plus state fees, then $99 a year for the agent

Editorial score 9.0 out of 10

Third, IL Registered Agent.org: $199 over the state fee to register in Illinois, agent renewing at $99.

You get an in-state street address as the registered office, and papers served there are scanned into your account.

IL Registered Agent.org lines up with Illinois Registered Agent.co on price and plan features, so little divides them.

In the price

  • Foreign registration done for you
  • A first year of registered agent service

Strengths

  • Year-two agent price: $99
  • A year of registered agent service comes in the price
  • Registers the company for $199, plus the state's fee

Cons

  • Illinois only; your home state needs its own agent
  • EIN application will cost you $99 more
Visit IL Registered Agent.orgPartner link. We may earn money if you buy. IL Registered Agent.org up close

The desk's 3 picks in brief

Pick Service Desk score Service fee Year two Good for Visit
1 Illinois Registered Agent.co 9.6 $199 $99/yr The lowest agent renewal we rank here Visit Illinois Registered Agent.coPartner link. We may earn money if you buy.
2 Mainstay Filing 9.1 $199 $149/yr Companies doing business in several states Visit Mainstay FilingPartner link. We may earn money if you buy.
3 IL Registered Agent.org 9.0 $199 $99/yr The lowest agent renewal we rank here Visit IL Registered Agent.orgPartner link. We may earn money if you buy.

Our editors assign each score out of 10 using the criteria on How we rank. Customer ratings play no part.

What a Illinois foreign registration service costs in 2026: year one, renewal and the three-year bill

Service Year one Year two Year three Bill over three years Agent covered in year one
Illinois Registered Agent.co $199 $99 $99 $397 Included
Mainstay Filing $199 $149 $149 $497 Free
IL Registered Agent.org $199 $99 $99 $397 Included

Every price here was read off the company's own pages on November 12, 2026. Illinois's $150 registration fee comes on top of every row and is left out of these totals.

Why it falls this way

Spend over three years made the call in Illinois. The desk weighs spend over three years and work the price removes at 33% each and gives what renewal looks like, fit with the state and plain price display the remaining 34%.

Illinois Registered Agent.co comes to $397 over three years, $100 less than Mainstay Filing. Both include a first year of agent service, so the renewal price made the call.

The full criteria and weights are on How we rank.

Registering a foreign LLC in Illinois: fee, form and who gets it

To register, the company files the Application for Admission to Transact Business (Form LLC-45.5) with the Illinois Secretary of State, Department of Business Services, Limited Liability Division and pays the state's $150. Illinois also wants certificate of Good Standing or Existence, issued within 60 days of the filing.

From then on the company owes the annual report ($75), due within the 60 days before your anniversary month.

What to pull together first

  • Certificate of Good Standing or Existence, issued in the 60 days before you file.
  • The company name exactly as the home state spells it, and when it was formed.
  • An in-state registered agent; any service the desk picked can fill that seat.
  • $150 for the state, paid when you file.
  • A date on your calendar for the annual report and its $75 fee.

What it costs to ignore Illinois registration

Until it registers, an outside LLC has no right to sue in Illinois courts (805 ILCS 180/45-45(a)). The contracts it signs stay good (805 ILCS 180/45-45(b)). Back fees for the years it operated unregistered come due too.

Illinois foreign registration service: reader questions

Does an LLC from elsewhere have to register to operate in Illinois?

Yes, once it starts doing business there. Until it registers it cannot sue in the state's courts.

What will foreign registration cost you in Illinois?

$150 goes to the state and $199 to the service.

What does Illinois call its foreign registration form?

It goes to the Illinois Secretary of State, Department of Business Services, Limited Liability Division, and the form's title is on the facts line above.

Will Illinois ask for something from your home state?

Yes: certificate of Good Standing or Existence, issued in the last 60 days.

Do you still need a registered agent after you register?

Yes. Keep a registered agent with a street address in the state on file.

Who is our pick for foreign registration in Illinois?

Illinois Registered Agent.co, since $199 plus the state fee, one year of registered agent service included, then $99 a year for the agent.

See also

Where the numbers came from

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