1 Dollar - Elizabeth II First Crossing of the Blue Mountains

The Blue Mountains west of Sydney defeated European explorers for over two decades after British settlement — the dense scrub and sheer sandstone escarpments made conventional valley-following routes impassable. Gregory Blaxland, William Lawson, and William Charles Wentworth finally crossed in May 1813 by keeping to the ridgelines rather than the gorges, reaching the western plains and opening the interior of New South Wales to pastoral expansion that would reshape the colony within a generation.

Cook Islands has issued commemoratives under this broad "exploration and discovery" program since the early 2000s, with KM#2363 among hundreds of similar-format issues produced for the collector market rather than circulation.