Hmmmm I find it interesting that Warren County has the highest median income in the Cincinnati metro area. Generally I've considered Butler County to be the wealthiest. I suppose I should have realized that the fast growing suburbs in Warren Co. would surpass Butler. All the new houses in Warren Co. are about twice the size of the ones in the Butler Co. suburbs.
Warren also included Hamilton and Middleton which were established cities before they became suburbs. Counties further out can be more purely suburbs. People are going to move their to buy a house. If they live an apartment, they can live in closer to the city.
Hamilton is actually the county seat of Butler County and while Middleton straddles both Butler and Warren Counties the majority of the city is in Butler. Warren Co. contains the fast growing city of Mason which is where most of the nice new houses I was referring to are being built. There is also significant growth in the county seat of Lebanon.