Manager Phil Woodcock’s side followed their 6-3 opening-day victory over Kent by defeating Cornwall 6.5-2.5.
With Lincolnshire and Kent sharing the honours in their match it left Yorkshire alone at the top as the only side with a 100 per cent record.
They face Lincolnshire in their final match when a half will be good enough for them to retain the national crown.
The foursomes were shared against Cornwall, with Rotherham’s Charlie Daughtrey and Jack Maxey (Hornsea) winning by one hole while Rotherham’s Ben Schmidt and Josh Berry, of Doncaster, halved.
But Yorkshire proved dominant in the afternoon singles session taking five wins out of six through Maxey, Schmidt, Middlesbrough’s Michael Hay, Abbeydale’s Jack Leversidge and Callum Macfie, of Lindrick.