A lawsuit to challenge a USCIS denial is ripe (or can be filed) when there is a “final agency action.” Basically, this is the denial. And the main tool to challenge a denial is the Administrative Procedure Act (APA). These lawsuits are filed in federal court. It is usually not necessary to file an administrative appeal before proceeding to federal court. Once there is a denial, a lawsuit can be filed. The denial itself is considered a “final agency action” or “final decision.” Most, if not all courts, that have considered the statute of limitations for APA case have held there is a 6 year time limit to bring your case once it becomes ripe. In other words, you have six years from the date of a USCIS denial to challenge it in federal court.