If you have lost your license tag or suspect it was stolen, file a police report and get a case number. You won't be able to replace your tag without that case number.
Call Dispatch non-emergency number at (785) 843-0250 and a deputy will stop by to take a report. If you reside outside the Douglas County Sheriff's Office jurisdiction, contact your local police department. Once you have the case number, apply for your new tag at the nearest Department of Motor Vehicles office.