Green’s Dictionary of Slang

1. the anus.

1592

Shakespeare Henry VI Pt 2 II ii: The rest of thy low-countries have made a shift to eat up thy holland.

2. the buttocks.

1787

Harris’s List of Covent-Garden Ladies 55: Soon as the vail is withdrawn, and the traveller has passed holland, he is [...] ravished with a view of the promised land, flowing with milk and honey.