Meander Boundaries for the Yellowstone River in Montana

I am working on a project to add the boundary meander lines of the Yellowstone River to Google Earth Pro. Since the results will be used for river access, it is very important that the boundaries are identical to Cadastral. I thought that I had found a source from Montana State Library, but after comparing the data against Cadastral, they definitely are not the same. I am a subscriber to Caltopo and compared the meander lines in Caltopo to Cadastral and find that they are identical. I am hoping that someone can point me to a Cadastral equivalent version of the meander lines.

Thanks