Selby lies on the tidal River Ouse in a natural area of Yorkshire known as the Humberhead Levels. The main roads which cross at Selby are the A63 from Leeds to Hull and the A19 from Doncaster to York, though the A19 and A63 no longer meet in Selby itself since the opening of the Selby Bypass in 2004. The River Ouse is navigable upstream as far as York so the old toll bridge by which the A63 crossed the river at Selby had to allow for this. For many years the swing bridge in Selby was a notorious local bottleneck but since the opening of the Selby bypass congestion in the town has been relieved.