Where to File for Divorce
State courts have power (or "jurisdiction") over divorce proceedings, so the spouse seeking a divorce files an initial document called a divorce "petition" or "complaint" with his or her state court -- usually in the county or district branch of the state's "superior" or "circuit" court. In some states, the superior or circuit court will have a specific family court division where the divorce petition is filed and the case is heard. In other states, no specific family court division is designated, so the divorce petition is filed in the main civil division of the superior or circuit court. In heavily populated areas, the county or district branch of the state court may itself have a number of facilities in different locations.
For example, in California the state's Superior Court handles divorces, and the California Superior Court has facilities in each county in the state. California requires that one or both divorcing spouses have lived in California for the previous six months AND have lived in one of the state's counties for the previous three months. So, a couple who has been living in Los Angeles county for the past four years would file a divorce petition in the Superior Court of California - County of Los Angeles. Since this court has a number of locations, the person(s) seeking a divorce would check the court's online Filing Court Locator in order to determine the proper courthouse where the case belongs. Check with the local county/district branch of your state's court to learn more about where to file for divorce.
State and County/District Residency Requirements
Most states have their own residency requirements for people who wish to file for divorce in the state's court system -- rules as to the length of time a spouse must reside in a state before filing for divorce there. For example, as mentioned above, California requires that one or both divorcing spouses have lived in California for the previous six months. Other states require residence within the state for as little as six weeks to as long as one year before filing for divorce.
Before filing for divorce, you will most likely need to comply with not only your state's residency requirements, but also local county or district residency requirements. Again, using California as an example, in order to file for divorce in the state you and/or your spouse must have lived in the state for six months AND in one of the state's counties for the previous three months. Check with the local county/district branch of your state's court to learn more about residency requirements for filing for divorce.
More on Divorce Residential Requirements, including a listing of durational residency requirements by state.