In addition to the powers vested in and exercised by county legislative bodies over public roads and bridges, the county legislative bodies respectively are empowered, the same being a county purpose, to build a bridge or bridges over and across any stream or river running through the county, which bridge shall be located on or near and convenient to a public highway, due regard being had both to advantages of location and convenience of the citizens of the county having to pass over the bridge, and may be located wholly or partly within the limits of any municipal corporation.