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Biz Formation Report

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

Foreign registration report · Illinois

3 Best Foreign Registration Services in Illinois (2026)

By the Biz Formation Report editorial team

Biz Formation Report ranks foreign registration services in Illinois for 2026 as Mainstay Filing ($199), IL Registered Agent.org ($199) and Illinois Registered Agent.co ($199), in that order. Mainstay Filing earns the top grade: the Illinois registration is filed for $199, and the registered agent is free in year one, then $149 a year.

No.1

Best here

1. Mainstay Filing: best for companies registered in several states

Score9.1out of 10
$199 service fee, $349 due at checkout with the state fee; the agent is $149 annually from year two

Top grade, Mainstay Filing: $199 added to the state fee in any state, with a year of registered agent service included.

Beyond the free first year, agent service is $149 annually in any state.

Over three years Mainstay costs $100 more than IL Registered Agent.org; our grading treats the broader coverage as worth that.

What you get

  • Registration prepared and filed on your behalf
  • A free first registered agent year
  • Same-business-day scanning of legal papers served, no fee

Good

  • Served papers scanned within the same business day, free
  • Registered agent at no cost in year one
  • One price across all fifty states
  • $199 service fee plus the state's fee

Weak spots

  • The agent renews at $149, $50 more than IL Registered Agent.org
Visit Mainstay FilingPartner link. We may earn money if you buy.
Read the Mainstay Filing review
No.2

Best local option

2. IL Registered Agent.org: best for companies adding Illinois alone

Score8.6out of 10
A $199 service fee and the state fee, then the agent at $99

Second grade, IL Registered Agent.org: $199 plus the state fee, one year of registered agent service included, then $99 a year for the agent.

The plan seats the company at an in-state street address and posts scans of papers served there to your online account.

What you get

  • The registration filing
  • The first year as your registered agent

Good

  • Registration costs $199 before the state fee
  • Then $99 per year for the agent
  • Includes a year of registered agent service

Weak spots

  • Serves Illinois only; the home state still needs its own agent
  • The EIN application costs $99 extra
Visit IL Registered Agent.orgPartner link. We may earn money if you buy.
Read the IL Registered Agent.org review
No.3

Best local option

3. Illinois Registered Agent.co: best for registering in Illinois only

Score8.3out of 10
A $199 service fee and the state fee, then the agent at $99

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

The plan seats the company at an in-state street address and posts scans of papers served there to your online account.

Illinois Registered Agent.co matches IL Registered Agent.org on price and plan features, leaving very little between them.

What you get

  • The registration filing
  • Year-one registered agent service

Good

  • A $199 registration price, state fee extra
  • $99 annually to keep the agent
  • First-year registered agent service is part of the price

Weak spots

  • Serves Illinois only; the home state still needs its own agent
  • The EIN application costs $99 extra
Visit Illinois Registered Agent.coPartner link. We may earn money if you buy.
Read the Illinois Registered Agent.co review

Summary of the 3 grades

RankProviderGradeService feeYear twoBest fitSite
1Mainstay Filing9.1$199$149/yrCompanies with a presence in several statesVisit Mainstay FilingPartner link. We may earn money if you buy.
2IL Registered Agent.org8.6$199$99/yrThe lowest agent renewal we rank hereVisit IL Registered Agent.orgPartner link. We may earn money if you buy.
3Illinois Registered Agent.co8.3$199$99/yrThe lowest agent renewal we rank hereVisit Illinois Registered Agent.coPartner link. We may earn money if you buy.

Our editors set each grade out of 10 from the weighted criteria on How we rank. Customers do not rate anything here.

Illinois foreign registration service prices, 2026: year one, renewal and three-year outlay

ProviderYear 1Year 2Year 3Three-year outlayYear-one agent covered
Mainstay Filing$199$149$149$497Free
IL Registered Agent.org$199$99$99$397Included
Illinois Registered Agent.co$199$99$99$397Included

All prices were taken from the companies' own websites on November 12, 2026. Illinois's $150 registration fee is payable on top of each row and is not part of these totals.

What decided the order

What the money buys was the deciding factor in Illinois. The method gives three-year bill and what the money buys 32% each and splits 36% across renewal handling, local rules match and pricing openness.

Foreign registration always involves two states, and one provider with one price in both graded best on coverage, ahead of IL Registered Agent.org.

Every criterion and weight is listed on How we rank.

Illinois foreign LLC registration: fee, document and filing office

To register, the outside company submits the Application for Admission to Transact Business (Form LLC-45.5) to the Illinois Secretary of State, Department of Business Services, Limited Liability Division, with a state fee of $150. Illinois also wants certificate of Good Standing or Existence, dated within 60 days of the filing.

After registration the company owes the annual report ($75), due within the 60 days before your anniversary month.

Documents to have on hand

  • Certificate of Good Standing or Existence, dated within 60 days of filing.
  • The legal name as recorded in the home state, and the date of formation.
  • An in-state registered agent; any provider in this report can serve.
  • Payment of the $150 state fee with the filing.
  • The due date of the annual report and its $75 fee, noted in your calendar.

The cost of skipping Illinois registration

An unregistered foreign LLC has no right to sue in Illinois courts until it registers (805 ILCS 180/45-45(a)). Its contracts remain enforceable (805 ILCS 180/45-45(b)). Fees owed for the unregistered period are collected as well.

Illinois foreign registration service: common questions

Must an LLC from another state register with Illinois?

Yes, as soon as it transacts business there. Until then it has no standing to bring a lawsuit in the state's courts.

How much does Illinois foreign registration cost?

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

Which form handles foreign registration with Illinois?

The state names the form in the facts above; it is sent to the Illinois Secretary of State, Department of Business Services, Limited Liability Division.

Does Illinois demand proof of good standing from the home state?

Yes. The filing needs certificate of Good Standing or Existence, issued no more than 60 days ago.

Is a registered agent still needed after foreign registration?

Yes. A registered agent with a street address in the state has to remain on file.

What is the best foreign registration service for Illinois?

Mainstay Filing: $199 plus the state's fee, with the registered agent free for year one and one price in every state.

See also

Source notes

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