If the boat will reside in Illinois, and you're going to register it in Illinois, then you have to register and title the trailer in IL as well. The only way you could get away with it is if the boat and trailer are registered in WI at a WI address, then the trailer doesn't need a plate, and doesn't need to be registered.

Just researched all this because I had debated just not bothering with Illinois, and using a friend's address in WI to register the boat and trailer I bought over the summer. Ended up just registering both in IL, and transferring title on the trailer and getting a plate.

From what I remember, if you have no title on the trailer, you have to apply for a "homemade trailer" title, I believe, from the Illinois DMV.

 

IIRC all of the above is accurate. My first boat was from WI as well.
In my case, I think I ended up having to hand write {i.e. invent} a bill of sale for the trailer {referencing the model # and serial #}. I then sent that info to the state of Illinois.

.

 

You asked if you needed to pay any money to the government, in the land of Tax and Spend? 21 21 21 21 21 21
HA!

If there is a way to get money out of your wallet, it will happen in Illinois, that's for sure!

PS... ESPECIALLY in CrOOK COUNTY

 

I got a bill from Cook County about a boat trailer I sold 10 years ago... They say I owe $250 in back taxes since I bought the boat in Kane County but registered it in Cook... I paid the RU-25 state sales tax, the SOS trailer and title tax, and the DNR boat tax/fee... 10 years later, Cook County says I still owe... You can pay them now or you can pay them late, but pay you will

 

We made a similar purchase, and the trailer did not have a title or plates. Even though it was clearly not a home-made trailer, because there was no paperwork that was the method to use with the Illinois secretary of state to obtain license plates.

Once submitted, I got a call from a secretary of state officer who made arrangements with me to to stop by and install a metal number plate to the trailer. Can't recall if he had the license plate with him or not, but it was all pretty easy.