Once widely used, the number of operational lighthouses has declined due to the expense of maintenance and their replacement by modern electronic navigational aids. Nearly all lighthouses today, that are still being used, are automated to the extent possible with power often provided via solar cells and large batteries in inaccessible areas. Today's lighthouses are all run by the U.S. Coast Guard the successor to United States Lighthouse Service. The list of active light houses, lighted beacons, etc. that provide detailed information on aids to navigation with their locations and characteristic signals is currently maintained by the U.S. Coast Guard in its Light List issued each year. California is presently in Eleventh and Thirteenth Coast Guard district.