LLC Review Desk's 2026 picks for registered agents in Illinois, favorite first, are Mainstay Filing ($149 a year), Illinois Registered Agent.co ($99 a year) and IL Registered Agent.org ($99 a year). Mainstay Filing is our favorite, because you pay $149 a year whether you stay in one state or grow, and your first three government letters each year are scanned free.
By the LLC Review Desk editorial team
Position 1
Our top pick in Illinois
1. Mainstay Filing: best for all fifty states
$149 a year, the same each year
Our score
9.3out of 10
9.3 out of 10
Our favorite is Mainstay Filing, because it's $149 a year and the price doesn't climb at renewal, plus papers served on the company get scanned the same business day for free.
Starting from scratch? The $199 yearly package adds the Illinois filing and the annual report.
Over three years it costs $150 more than Illinois Registered Agent.co, and for us the extra things it handles are worth that.
In the price
A registered office street address wherever you need one
Papers served on the company are scanned and uploaded the same business day, free
Free scans of your first three government letters each year
Compliance reminders
What we like
Fine for LLCs, corporations, LPs, LLPs and nonprofits
Same-business-day scans of papers served on the company, no charge
Your first three government letters each year, scanned for free
$149 a year and it stays flat
Trade-offs
The agent plan alone is $50 a year more than Illinois Registered Agent.co
Report filing comes with the formation package, not the agent plan
2. Illinois Registered Agent.co: best for the smallest yearly price on this list
$99 a year, the same each year
Our score
9.1out of 10
9.1 out of 10
Coming in second is Illinois Registered Agent.co, because you pay a flat $99 a year, and papers served on the company are scanned into your account.
The registered office you get is Illinois Registered Agent.co's address inside the state, and you read whatever is served on the company as a scan online.
In the price
A registered office address inside the state
Every legal paper served on the company is scanned and stored in your account
What we like
Beats Mainstay Filing on yearly cost
Forms LLCs too, and the first agent year is free
$99 annually with no renewal bump
Trade-offs
The Limited Liability Company Annual Report is a job that stays with you
Built for Illinois; other states need another agent
Our scores out of 10 are editorial: LLC Review Desk sets them using the criteria on How we rank. They aren't customer ratings.
What Illinois registered agents cost in 2026: year one, renewals and three years
Service
First year
Second year
Third year
Three-year total
Same price when you renew
Mainstay Filing
$149
$149
$149
$447
Yes
Illinois Registered Agent.co
$99
$99
$99
$297
Yes
IL Registered Agent.org
$99
$99
$99
$297
Yes
We took each price from the company's own pages on November 12, 2026. Illinois's own fees stay the same no matter which agent you choose.
Why we ordered them this way
Two things count most to us, three-year cost and filings in the price, at 29% each. Renewal price, state fit and up-front totals share 42%, and Illinois came down to filings in the price.
Mainstay's plan does more: it scans papers served on the company the same business day, free, and the price is the same in all fifty states, with three government letters a year scanned at no charge. Illinois Registered Agent.co costs less, so it's a close race.
You can read every criterion and weight on How we rank.
What Illinois says about the registered agent (via Illinois Secretary of State)
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. The law: 805 ILCS 180/1-35.
The Illinois Limited Liability Company Annual Report: when and how much
Here's the schedule: the Limited Liability Company Annual Report is due every year in Illinois, by before the first day of the entity's anniversary month. It costs $75. If you're late, add $100. Reminders from the state go to your registered agent.
Your questions about Illinois registered agents
Do I really need a registered agent for an Illinois LLC?
You do. Illinois won't accept an LLC without a registered agent who has a street address in the state, and that name goes on the public record.
What do Illinois registered agents usually cost per year?
Plan on $99 to $149 a year, and each service keeps its price when you renew.
Can I be my own registered agent?
Sometimes, if you meet the state's rules. An Illinois resident, or a business authorized to do business in Illinois. The LLC cannot act as its own agent.
When do I have to send in the Illinois Limited Liability Company Annual Report?
Mark before the first day of the entity's anniversary month on your calendar. The state's charge is $75, and sending it late tacks on $100.
Which registered agents did we review here?
Mainstay Filing ($149 a year), Illinois Registered Agent.co ($99 a year) and IL Registered Agent.org ($99 a year), with our favorite first.
Who is the best registered agent for Illinois?
Mainstay Filing, because one plan, $149 a year, follows the company to any state and renews at $149.