3 Best LLC Services in Illinois (2026): Who to Ask First
In Illinois for 2026, our answer on LLC formation services is Mainstay Filing ($199), IL Registered Agent.org ($199) and Illinois Registered Agent.co ($199), ranked from first to last. Every option pays Illinois $150 to file, then charges $397 to $597 for three years of service.
Answered by the Ask About LLC editorial team ·
The short answers
State fee to file
$150, paid once
What comes after?
$75 a year
Registered agent
Yes, name one
Who to ask
Mainstay Filing, IL Registered Agent.org then Illinois Registered Agent.co
Our Illinois answer, best first
The order follows our five questions: three-year cost first, then how much the price covers.
1Ask this one first
1. Mainstay Filing: best for owners who want upkeep handled
Annual price $199, renewal price $199, state fee on top
Mainstay Filing is the one to ask first in Illinois because $199 a year includes the formation, the registered agent and every annual report.
Over three years this costs $200 more than IL Registered Agent.org, and you hand off more filings in return.
The Limited Liability Company Annual Report gets filed by Mainstay Filing, and Illinois's $75 is passed on at cost.
One filing keeps coming back: the Limited Liability Company Annual Report, each year, for $75. The state says it is due before the first day of the entity's anniversary month.
A service is optional. State fees alone are $300 across three years.
Expect $397 to $597 more over three years if you hire someone.
Why is the list in this order?
Chores the price takes care of counts 29%, and Mainstay Filing leads there.
We weigh five questions: what you pay over three years (33%), chores the price takes care of (29%), answers on the price page (14%), what happens at renewal (13%) and room to add states (11%).
IL Registered Agent.org is the smaller bill, but you would still prepare the Limited Liability Company Annual Report yourself.
How was the bottom line figured? Add the filing fee, the next two reports and the minimum tax if the state has one. Anything with no fixed price, a newspaper notice for instance, is described above and kept out of the sum.
Questions people also ask
Is the EIN application included?
Mainstay Filing includes the EIN application. The others charge extra: IL Registered Agent.org $99; Illinois Registered Agent.co $99.
Is there a late fee?
Expect a $100 late fee.
What do the picks cost over three years?
Three-year totals: Mainstay Filing $597, IL Registered Agent.org $397, Illinois Registered Agent.co $397, before state fees.
Are the fees official?
Official Illinois sources back the state side, and posted company prices back the service side.
Do I have to use a service?
No. What the law asks for is a filing, and it does not say who has to send it.
Which one do you recommend in Illinois?
Ask Mainstay Filing first, then compare IL Registered Agent.org and Illinois Registered Agent.co.
Where did we look this up?
Our answer on Illinois Secretary of State, Department rests on ilsos.gov, a page we confirmed August 2026 and still point you to
Our answer on Illinois Secretary of State, Department rests on ilsos.gov, a page we confirmed August 2026 and still point you to
Our answer on 805 ILCS 180/5-5 rests on ilga.gov, a page we confirmed August 2026 and still point you to
Our answer on Illinois formation fee: Filing fee rests on ilga.gov, a page we confirmed October 2026 and still point you to
Our answer on Illinois formation fee: Filing fee rests on ilsos.gov, a page we confirmed October 2026 and still point you to
Our answer on Illinois registered agent statute rests on ilga.gov, a page we confirmed October 2026 and still point you to
Mainstay Filing Illinois service page, read November 13, 2026
IL Registered Agent.org pricing page, read November 13, 2026
Illinois Registered Agent.co pricing page, read November 13, 2026