As previously stated, KRN is Kern County Fire Departments 3-Letter identifier.
KCFD is one of the six “contract counties” for CALFIRE. These 6 counties provide the initial attack Wildland firefighting resources and are provided an annual budget from CALFIRE for doing so.
CALFIRE provides Wildland fire protection in done form in the other 52 counties in CA. Further, CALFIRE has their jurisdictions broken down into “Units” rather than by county, and each have a 3-letter identifier that ends with a “U” (standing for UNIT). Most CALFIRE Units encompass multiple counties.
The six CALFIRE Contract Counties and their identifiers are as follows:
MRN- Marin County Fire (only NorCal contract county)
KRN- Kern County Fire
LAC- LA County Fire
ORC- Orange County Fire
VNC- Ventura County Fire
SBC- Santa Barbara County Fire
Hope this helps 
Just for accuracy, there are 2 counties that have no State Responsibility Area (SRA), San Francisco County and Sutter County. Sutter County is interesting in that the Sutter Butte’s, known as the smallest mountain range in the world, it is all private land except 1 area that was given to the state as a park but it is ‘landlocked’ with public easement.
Very interesting ty
Had a little heat next to the line.
Should we be posting here?
That would be the proper thread.
Wasn’t sure since it was declared contained.