Carquinez Strait Powerline Crossing was the world's first powerline crossing of a large river. It was built in 1901 for a 60 kV powerline operated by Bay Counties Power Company to deliver electric power to Oakland, California. For this a crossing of Carquinez Strait was required, which has at its narrowest point a width of 1 kilometre (0.62 mi). Such a span width was impossible with wooden poles, which were common in those days.