You can purchase these and other maps at the ARRL Store.

ARRL Amateur Radio Map of North America -- 27 x 39 inches. Large, colorful wall map features current geographic detail and labels, grid squares, call sign prefixes, boundaries and more.

ARRL Grid Locator for North America -- Size 11" x 17"

The ARRL World Grid Locator Atlas -- Containing all 32,400 Maidenhead Locator Squares.