Federal laws apply in every part of the United States, while state laws apply to local areas within a state, explains LawHelp.org. Federal laws typically involve issues such as immigration, bankruptcy, civil rights, patents and copyright, and taxation. State laws, on the other hand, often deal with criminal issues, divorce and other family matters, business contracting, welfare and property. Municipal laws relate to issues such as rents, zoning and safety.
Article VI of the U.S. Constitution deems federal laws "the supreme law of the land," which constitutes "preemption," explains Exploring Constitutional Law. Where federal law unambiguously preempts state law, the state law is invalid. However, courts must often consider the intention of federal laws in cases in which Congress's intention is unclear, and when the intention may not have been, at the time of its passing, to block a state's autonomy in a particular issue.
Different state laws are also often heard by different state courts, with many states having separate juvenile, family, probate and other courts, notes the United States Courts website. Federal courts normally hear constitutional issues and matters relating to international treaties, inter-state disputes, human rights violations and public officials. State courts most often hear legal disputes pertaining to contracts and personal injuries, as well as criminal conduct. State courts hold the final authority to determine the outcome of disputes regarding state laws, unless there is an issue of conflicting federal law or constitutionality, in which case they may be appealed to U.S. District Courts, Courts of Appeal or the U.S. Supreme Court.