One who sells the goodwill of a business may agree with the buyer to refrain from carrying on a similar business within a specified county and any county or counties contiguous thereto, or a specified city or town or any part thereof, so long as the buyer, or any person deriving title to the goodwill from him carries on a like business therein. Provided, that any such agreement which is otherwise lawful but which exceeds the territorial limitations specified by this section may be deemed valid, but only within the county comprising the primary place of the conduct of the subject business and within any counties contiguous thereto. R.L.1910, § 979.
Oklahoma Legal Code