Might not be universal but we have Charter and Incorporated Cities which are carved out of counties... Cities come with another layer of laws and regs on top counties.
County may have Sheriff Departments and city Police Departments.
Of course some cities grow so big they encompass the entire county... case in point City and County of San Francisco.
The reason asked is curiosity because when I read posts clearing land, timber, farming... it is hard to relate when I need a formal permit with public hearing over 6 weeks to remove a single planted Walnut Tree or having LEO called because I am Brush Hogging the back 20...