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Founder Mentor Guide

Walkthrough 3 · Illinois

Foreign LLC Registration Walkthrough, Illinois (2026): 5 Stages and the 3 Best Services

Ranked for 2026, the services worth your call for bringing an LLC into a second state in Illinois are Illinois Registered Agent.co ($199), Mainstay Filing ($199) and IL Registered Agent.org ($199), in that order. Illinois wants $150 from a foreign LLC, and the 5 stages below show you how to file.

Advice from the Founder Mentor Guide mentors

Read this first

What the state charges to register
$150
ilsos.gov, seen in October 2026
Certificate you must attach
60 days
No older than
Maintenance filing
$75
Annual report
What the state collects in three years
$300
Registration, reports and any minimum tax
Stages
5
One at a time

Walkthrough goals

  • Whether Illinois registration applies to your LLC
  • The filing, its price and its office
  • What staying registered costs
  • Which services we recommend and why

Who we would phone in Illinois

Ranked on the scoring page: three-year cost (32%), work taken off your desk (32%), year-two price, fit with Illinois rules and honest pricing.

Our call

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

Our first call$199 to register, $99 a year after

Illinois Registered Agent.co is our first call in Illinois: a service fee of $199 and an agent renewal of $99 a year.

Because Mainstay Filing costs more over three years, this service takes the top spot.

What you get

  • The registration filing
  • Agent service for one year comes with the price

What works

  • Agent covered in year one
  • $199 above the state fee
  • Then $99 per year

What to watch

  • A single-state service
Visit Illinois Registered Agent.coPartner link. We may earn money if you buy.

Our call

2. Mainstay Filing: best for a string of registrations

Does the most for you$199 to register, $149 a year after

Mainstay Filing comes in second: you pay $199 on top of the state fee, the registered agent costs nothing in year one, and after that it is $149 a year.

Illinois Registered Agent.co comes in $100 cheaper across three years, enough to keep this one out of first.

After the included year, count on $149 per year for the agent, wherever you register.

What you get

  • Filing made with the state
  • Your first year of registered agent is free
  • Covers all fifty states

What works

  • Registered agent is free in year one
  • Any state, one fee
  • $199 on top of Illinois's fee

What to watch

  • Renewal $50 above Illinois Registered Agent.co's
Visit Mainstay FilingPartner link. We may earn money if you buy.

Our call

3. IL Registered Agent.org: best for registering only in Illinois

Illinois specialist$199 to register, $99 a year after

Pick number 3 is IL Registered Agent.org, where a service fee of $199 and an agent renewal of $99 a year.

It lists the same prices as Illinois Registered Agent.co.

What you get

  • The registration filing
  • Agent service for one year comes with the price

What works

  • Then $99 per year
  • $199 above the state fee
  • Agent covered in year one

What to watch

  • A single-state service
Visit IL Registered Agent.orgPartner link. We may earn money if you buy.

The Illinois picks side by side

#ServiceFirst yearFrom year twoThree-year total
1Illinois Registered Agent.co$199$99/yr$397Visit Illinois Registered Agent.coPartner link. We may earn money if you buy.
2Mainstay Filing$199$149/yr$497Visit Mainstay FilingPartner link. We may earn money if you buy.
3IL Registered Agent.org$199$99/yr$397Visit IL Registered Agent.orgPartner link. We may earn money if you buy.
Company prices as listed on November 13, 2026. The $150 state fee comes on top of each row.

The stages

  1. Stage 1

    Check whether Illinois wants your LLC to register

    Foreign registration is how an LLC from another state gets permission to do business in Illinois. Skipping registration can hurt: an unregistered LLC cannot be a plaintiff in Illinois (805 ILCS 180/45-45(a)) its contracts can still be enforced (805 ILCS 180/45-45(b)) unpaid fees from earlier years

    Check it yourself: ilga.gov, seen in October 2026

  2. Stage 2

    Ask the home state for proof of good standing

    You will need certificate of Good Standing or Existence, from within 60 days.

    Request it close to your filing date.

  3. Stage 3

    Arrange an Illinois registered agent

    Every LLC must name a registered agent with an in-state street address. The address has to be a registered office in Illinois that matches the agent's business office. A P.O. box alone is not accepted.

    Our picks each fill the registered agent role.

    Check it yourself: ilga.gov, seen in October 2026

  4. Stage 4

    Time to send in the Application for Admission to Transact Business

    the Illinois Secretary of State, Department of Business Services, Limited Liability Division receives the filing above and $150.

    Check it yourself: ilsos.gov, seen in October 2026

  5. Stage 5

    Look ahead to the repeating filing

    After registering, a foreign LLC sends in the annual report ($75), within the 60 days before your anniversary month.

Illinois costs by stage

StageWho gets paidTotal
The registration stageState office$150
Annual reportState office$75
Service, if you hire oneThe service company$199 in the first year
State fees, years one to threeState office$300
Add the filing fee, two later reports and any minimum tax and you have the state's three-year total. The pages listed below show where each figure came from.

Why Illinois Registered Agent.co is first

What decided it was three-year bill, which carries 32% of the score.

Three years with Illinois Registered Agent.co cost $397, which is $100 under Mainstay Filing.

Illinois questions answered

How big is the Illinois fee for a foreign LLC?

$150 in state fees. The services here charge $199 extra.

Which form do I file to register?

Foreign LLCs send this form to The Illinois Secretary of State, Department of Business Services, Limited Liability Division.

Do I need a certificate from my home state?

Yes: certificate of Good Standing or Existence, issued within 60 days of filing.

What if the LLC does business there without registering?

an unregistered LLC cannot be a plaintiff in Illinois (805 ILCS 180/45-45(a)) its contracts can still be enforced (805 ILCS 180/45-45(b)) unpaid fees from earlier years

What is due after registering?

After registering, the LLC will owe the annual report, at $75 per filing.

Which service should handle the registration?

Illinois Registered Agent.co, Mainstay Filing and IL Registered Agent.org, from the top score to the lowest.

Where we got the facts

  1. Illinois Secretary of State, Department of Business Services: go straight to ilsos.gov, checked August 2026.
  2. Illinois Secretary of State, Department of Business Services: go straight to ilsos.gov, checked August 2026.
  3. 805 ILCS 180/5-5: go straight to ilga.gov, checked August 2026.
  4. Illinois formation fee: Filing fee, official source: go straight to ilga.gov, checked October 2026.
  5. Illinois formation fee: Filing fee, official source: go straight to ilsos.gov, checked October 2026.
  6. Illinois registered agent statute: go straight to ilga.gov, checked October 2026.
  7. Form LLC-45.5, Application for Admission: go straight to ilsos.gov, checked October 2026.
  8. Form LLC-45.40, Application for Withdrawal: go straight to ilsos.gov, checked October 2026.
  9. 805 ILCS 180/45-45, consequences of transacting business without: go straight to ilga.gov, checked October 2026.
  10. 805 ILCS 180/45-47, activities that are not transacting: go straight to ilga.gov, checked October 2026.
  11. 805 ILCS 180/45-45: go straight to ilga.gov, checked November 2026.
  12. We opened Illinois Registered Agent.co's pricing page on November 13, 2026 for the prices
  13. We opened Mainstay Filing's Illinois service page on November 13, 2026 for the prices
  14. We opened IL Registered Agent.org's pricing page on November 13, 2026 for the prices