Castle Hill is an isolated pink granite

Granite

Granite is a common and widely occurring type of intrusive, felsic, igneous rock. Granite usually has a medium- to coarse-grained texture. Occasionally some individual crystals are larger than the groundmass, in which case the texture is known as porphyritic. A granitic rock with a porphyritic...

 monolith

Monolith

A monolith is a geological feature such as a mountain, consisting of a single massive stone or rock, or a single piece of rock placed as, or within, a monument...

 standing in the heart of the north Queensland

Queensland

Queensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...

 city of Townsville. It rises to a height of some 286 metres above sea

Sea

A sea generally refers to a large body of salt water, but the term is used in other contexts as well. Most commonly, it means a large expanse of saline water connected with an ocean, and is commonly used as a synonym for ocean...

 level and dominates the city skyline

Skyline

A skyline is the overall or partial view of a city's tall buildings and structures consisting of many skyscrapers in front of the sky in the background. It can also be described as the artificial horizon that a city's overall structure creates. Skylines serve as a kind of fingerprint of a city, as...

. It is one of the most distinctive natural features on the Queensland coast. There are a number of vantage points from which to view the city below and also across Cleveland Bay to nearby Magnetic Island

Magnetic Island

Magnetic Island is an island offshore from the city of Townsville, Queensland, Australia. This mountainous island in Cleveland Bay has effectively become a suburb of Townsville, with 2,107 permanent residents. The island is accessible from Townsville Breakwater to Nelly Bay Harbour by ferry...

.
The hill is an inselberg of Carboniferous

Carboniferous

The Carboniferous is a geologic period and system that extends from the end of the Devonian Period, about 359.2 ± 2.5 Mya , to the beginning of the Permian Period, about 299.0 ± 0.8 Mya . The name is derived from the Latin word for coal, carbo. Carboniferous means "coal-bearing"...

-Permian

Permian

The PermianThe term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian...

 origins, rising abruptly from the younger Quaternary

Quaternary

The Quaternary Period is the most recent of the three periods of the Cenozoic Era in the geologic time scale of the ICS. It follows the Neogene Period, spanning 2.588 ± 0.005 million years ago to the present...

 coastal plain.