This is a Colonial Williamsburg salt glazed mug or stein, decorated in cobalt blue over a grey background. It is 4 1/2" tall and 3 1/8" wide at the top. The mug is in excellent condition with no chips or cracks. It has an incised Williamsburg Souvenir mark on the base in an oval. There are also some other words I can't make out across the top of the oval.
Colonial Williamsburg Cobalt Blue Salt Glazed Leaf Pattern Mug