The Blue & John Crow Mountains
To the casual observer looking east from Kingston, the mountains of Jamaica appear as a singular, undulating wall of green. However, for geographers and historians, this landscape is a tale of two distinct worlds. The Blue and John Crow Mountains form a continuous mass, yet they are separated by a deep physical and geological divide.
The Blue Mountains
Rising to 2,256 meters, 7,402 feet at the Peak, these are ancient metamorphic and volcanic formations. They are characterized by steep, shaly slopes and "Elfin" mist forests at high altitudes. This is the domain of the world-famous Arabica coffee.
The John Crow Mountains
To the East, the John Crow range is a rugged, tilted plateau of limestone. It rarely exceeds 1,140 meters, with its highpoint at 1,143 meters, 3,750 feet, but is far more difficult to traverse due to "Karst" topography—a labyrinth of razor-sharp rocks, sinkholes, and underground caves.
📍 A Note on the "John Crow" Name
It is a common point of confusion: John Crow Peak is actually located in the Blue Mountains (St. Andrew), not the John Crow Mountains.
While both are named after Jamaica’s ubiquitous turkey vulture, they belong to entirely different geological systems. The John Crow Mountains represent the distinct limestone plateau to the east of the Rio Grande Valley.
The Geographic Anchor: Corn Puss Gap
The primary boundary between these two ranges is Corn Puss Gap. This saddle-like pass, sitting at approximately 640 meters (2,100 ft), serves as the topographic divide where the two ranges meet. The relationship is further defined by the Rio Grande, one of Jamaica’s largest rivers. Running north to the sea, the river carves a massive valley that separates the high-altitude volcanic peaks of the Blue Mountains to the west from the limestone-based John Crow range to the east.
While the Blue Mountains run roughly West-to-East, the John Crow Mountains run more northwest to southeast (parallel to the northeast coast). This intersection at Corn Puss Gap creates a "Y" shape in the topography of eastern Jamaica, forming a massive watershed that feeds the island's most fertile regions. Historically, it served as a significant route for the Windward Maroons, connecting the Rio Grande Valley to the southern coast. Today it is a hiking access and remains a key landmark for hikers traversing the rugged terrain of the Blue and John Crow Mountains National Park.
The Border Corridor: From Gap to Valley
While Corn Puss Gap (18.0037° N, 76.3520° W) serves as the primary geological junction, the border between these two giants is best understood as a rugged corridor. From this gap, the divide extends northwest toward the Millbank area, following the deep trench of the Rio Grande Valley.
The Millbank Intersection
In the vicinity of Millbank and Ambassabeth, the landscape is uniquely "sandwiched." To the west rise the steep, shaly spurs of the Blue Mountains; to the immediate east, the terrain rockets upward into the tilted limestone plateau of the John Crows. This narrow valley was the primary theater of the Windward Maroons, providing a hidden artery for movement between the north and south coasts.
Today, this corridor remains a vital "ecotone"—a meeting place of volcanic and limestone soils—where 40% of the island's endemic flowering plants overlap in one of the most biodiverse regions of the Caribbean.
