Milton has a population of approximately 20,000 persons and covers 23,000 acres. The area is double the physical size of the city of Alpharetta with half its population. The new city includes the northwest unincorporated island that is bordered by Cherokee County to the north and west; Forsyth County to the east; Roswell city limits to the southwest (a little west of Arnold Mill Road); Alpharetta city limits to the south (roughly, Mayfield Road to Cogburn Road to Windward Parkway).

The new city will continue to be a part of Fulton County with County Commission representation. The difference is now most services will be decided by local City Council members rather than Fulton County commissioners.