I just did it a few weeks ago. Actually, it was pretty straightforward. Tell the officer that you are importing a trailer. They will ask you to park your vehicle and go inside to meet with an officer. The officer will ask to see your driver’s license, purchase agreement and your trailer’s Canadian’s registration. Once the serial number is verified, the officer will complete an “Entry Summary / Release form which you sign and they stamp with date and crossing ID. Your done until you register it with your state’s DMV. Our state requires the following documentation: Registration/title, Custom’s Entery Summary, Homeland Security form HS-7 (which you complete - customs no longer completes the form), copy/photo of the N56 sticker (left side of trailer), copy of purchase agreement, and finally a copy of my wire transfer (verify what you paid in US funds). I got my plates with the understanding the State may ask for more documentation. Good luck.