I am a grandparent who is trying to establish guardianshio of 2 minor children who you have raised since birth but you now live in a different state

"Home state" is defined under the UCCJEA, where the children have resided over the last 6 months. If the children have been with their mother for 6 months in Michigan, in order for you to fight to get custody of the children, you would have to do it in a Michigan court room. If the children only recently left the state of Wisconsin and are now with the children in Michigan, Wisconsin would retain "home state" jurisdiction for 6 months after the point in time they lived here in the state of WI. That is the jurisdictional answer to your question.      If there is an underlying family law case, you can petition to have custody of the child, providing the court makes a finding that both parents are unfit or otherwise unable to take care of the child. If there is no underlying family court case, your remedies lie in children's court by filing a CHIPS petition or asking for legal guardianship in probate court. Again, both parents would have to be noticed of your request and have the right to object. If both are not unfit or otherwise unable to take care of the children, you will have a very difficult time pursing custody. You should consider sitting down and talking to an experienced family lawyer on what your chances might be, how long it is going to take, where you need to do it (Michigan or Wisconsin) and what the cost might be to pursue custody, before proceeding any further.