usa - county level emergency services

most counties in the usa have police patrol units operated by the
county sheriff department - they typically patrol the unincorporated
areas - ( and any cities or towns that contract for their services )

massachusetts does not have these types of units - dont think that New
Jersey or Connecticut have them either - all other states seem to have
them

county / countywide ambulance services do not exist in New England -
nor New York - nor New Jersey - nor Pennsylvania - nor Maryland - 99%
sure of this - (just thought of one New England exception - nantucket
county has 1 ambulance service - but its a 1 town island with 1 FD)

the rest of the states do seem to have county ambulance services -
except maybe for California - ( but all of their ambulance coverage is
arranged and heavily regulated via the county governments )

for fire services - the only states that have true countywide FDs are
Georgia - and maybe some of the most rural Texas counties - maybe some
really small 'one town' counties in Kansas and Nebraska also

Florida has many county FDs but none of them seem to be 100%
countywide - usually the county seat has a seperate FD - SC has county
FDs also but none seem to be 100% countywide