Jurisdictional issues in divorce can be both confusing and high-stakes. Here in the Coulee region, they can also be quite common. Different jurisdictional rules apply for divorce, legal separation, paternity, child custody and child support, but courts will almost always ensure that related issues (for example, custody and support) are heard by a single court and not split between jurisdictions. And within the bounds of those rules, it is often the first party to file that has the advantage in setting the forum where the case will be heard.
People generally have two questions about jurisdiction: Which court can hear my case? And, if I have a choice, which court should I choose to file my case in (or move my case to)? Where there is a choice, it can be between states (e.g. Minnesota vs. Wisconsin) or between counties (e.g. La Crosse County vs. Vernon County). The difference in state law can be very significant when it comes to property division, custody, support, and spousal maintenance (aka alimony). All counties within a state follow the same laws, but local practices and procedures can differ between counties, and of course the commissioners and judges who sit in those counties are different people, and each one may take a different view of the case in ways that substantially affect the outcome.
Some rules of thumb: under Wisconsin or Minnesota law, a divorce case can be filed in the state where either party has lived for at least six months, in the county where that party has lived for at least 30 days. Legal separations do not have the six-month requirement, so can be filed after only 30 days living in a particular county. An independent custody case (including post-divorce motions) typically belongs in the last state where the child in question lived for six consecutive months...but if jurisdiction is still in a different state, a motion must first be filed in that state asking that it relinquish jurisdiction of the case.
Once properly filed, divorce and legal separation cases are unlikely to be moved. On the other hand, custody and support cases may change venue (counties) and jurisdiction (states) over time, as the parties and child relocate. Even though the rules are designed to be clear and consistent, even the idea of where a party or a child "resides" can be a fluid one open to interpretation and requiring the support of evidence. With the thicket of rules surrounding jurisdiction and the potentially great consequences of litigating in a less favorable or distant jurisdiction, seeking legal counsel is your best bet for landing in the best possible court for your case.