Skip to content
LLC UnpackedEvery filing, unpacked: the fee, the form, the catch.

Open it up · Illinois

3 Best Foreign Registration Services in Illinois (2026), Opened Up

Our 2026 stack of foreign registration services in Illinois, top to bottom: IL Registered Agent.org ($199), Mainstay Filing ($199) and Illinois Registered Agent.co ($199). Every option pays the state $150, then services total $397 to $497 across three years.
Unpacked by the LLC Unpacked editorial team

Top layer

Registration fee
$150
Certificate packed in?
Yes (60 day age cap)
Once registered
$75, annual report
Top of the stack
IL Registered Agent.org, Mainstay Filing then Illinois Registered Agent.co

Our Illinois picks, opened up

Prices come from each company's own page. See how we open it up.
Top of the stack

1. IL Registered Agent.org: best for adding only this state

$199 to register; agent renewal $99

IL Registered Agent.org sits on top in Illinois because it charges $199 with first-year agent service inside, then $99 annually.

Cost decides it: the three-year total here is under Mainstay Filing's.

Inside the price

  • Illinois registration filing
  • A first year of agent service

Inside, the good

  • A renewal of $99
  • $199 plus the state fee
  • A free agent year at the start

Inside, the catch

  • Illinois only, so the home state needs its own agent
All fifty states

2. Mainstay Filing: best for adding state after state

$199 to register; agent renewal $149

What puts Mainstay Filing second: registering costs $199, and the registered agent comes free until year two.

IL Registered Agent.org totals $100 less across three years, enough to outrank it.

The registered agent is not charged in year one and costs $149 a year after that, in any state.

Inside the price

  • The registration filing, included
  • Registered agent, not charged in year one
  • The same fee in all fifty states

Inside, the good

  • $199 over the state fee
  • Agent costs nothing the first year
  • Identical fee in every state

Inside, the catch

  • Agent renews at $149, $50 above IL Registered Agent.org
The Illinois specialist

3. Illinois Registered Agent.co: best for one added state, no more

$199 to register; agent renewal $99

Illinois Registered Agent.co sits third because it charges $199 with first-year agent service inside, then $99 annually.

It charges what IL Registered Agent.org charges.

Inside the price

  • Illinois registration filing
  • A first year of agent service

Inside, the good

  • A free agent year at the start
  • $199 plus the state fee
  • A renewal of $99

Inside, the catch

  • Illinois only, so the home state needs its own agent

Inside each price

#CompanyYear oneRenewalTotal, 3 yearsWhat is inside
1IL Registered Agent.org$199$99/yr$397illinois registration filing; A first year of agent serviceOpen IL Registered Agent.orgPartner link. We may earn money if you buy.
2Mainstay Filing$199$149/yr$497the registration filing, included; registered agent, not charged in year one; the same fee in all fifty statesOpen Mainstay FilingPartner link. We may earn money if you buy.
3Illinois Registered Agent.co$199$99/yr$397illinois registration filing; A first year of agent serviceOpen Illinois Registered Agent.coPartner link. We may earn money if you buy.
Service fees only, from company prices read November 13, 2026. State fees are the same whichever pick you open.

Layer by layer

Does my LLC from another state have to register?

Any LLC formed elsewhere should file its registration with the Illinois Secretary of State, Department of Business Services, Limited Liability Division ahead of its first Illinois transaction.

Inside the risk of skipping it: Illinois's courts stay closed to it as a plaintiff until it registers (805 ILCS 180/45-45(a)); back fees for the months it ran unregistered.

peek at ilga.gov, confirmed October 2026

What is inside the cost of registering?

The state charges $150, and a service adds $199.

Over three years the state's fees reach $300, counting any recurring report. peek at ilsos.gov, confirmed October 2026

Which form is inside the filing, and where does it go?

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

Pack in certificate of Good Standing or Existence issued within the last 60 days.

What is due after the LLC registers?

Next in the box: the annual report, at $75.

The state frames the deadline as Within the 60 days before your anniversary month.

What put number one on top?

IL Registered Agent.org is strongest on total across three years, a layer worth 34% of the score.

Five layers set the order: total across three years (34%), what is inside the price (29%), price laid out in the open (14%), how the renewal behaves (12%) and how far it reaches (11%).

IL Registered Agent.org stacks up to $397 over three years, $100 under Mainstay Filing.

The five layers

Illinois registration, unpacked

RequirementAmount or rulePeek at source
Fee to register$150peek at ilsos.gov, confirmed October 2026
Certificate from homeYes, 60 dayspeek at ilga.gov, confirmed October 2026
Annual report$75peek at ilga.gov, confirmed October 2026
State fees, years one to three$300The rows above, stacked
Last row = filing fee + two later reports + minimum tax, if the state has one. Variable costs are described in the text, not added.

More boxes to open

Do I still need an agent in my home state?

Yes. Think of two separate rule books, your home state's and this one's. Mainstay Filing works in both, so a single account can serve the pair.

How do the three-year totals compare?

IL Registered Agent.org stacks up to $397, Mainstay Filing stacks up to $497, Illinois Registered Agent.co stacks up to $397, with state fees on top.

Are the fees official?

The state-side figures were taken from Illinois's own publications, and the service prices from the price page each company posts. Dates for both appear on this page.

Does the law require one?

Not required. The state takes filings from owners.

Will a service file the registration for me?

Each company here handles the filing itself. What differs between them is only the service fee, since the state charges the same.

Which foreign registration service should I open first in Illinois?

IL Registered Agent.org, because three years of its service fees come to $397. Then Mainstay Filing and Illinois Registered Agent.co.

What the page rests on

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