Long before any surveyor sketched it, this monolith had a name: Cutheringa, also written Cootharinga or Cooderinga. The Wulgurukaba of Garumbilbarra, the Traditional Owners of this country, hold the hill in deep spiritual significance, and it features in their Dreaming. Much of that knowledge was never written down by outsiders, but the name endured against long odds. Today Cutheringa is one of only two Aboriginal place names that survive across the whole Townsville region; the other is Pallarenda, the cape a few kilometres up the coast. When Andrew Ball, one of the first Europeans to explore the Ross River in April 1864, looked at the rock, he reached for home instead, naming it for a hill he thought resembled one near Dublin or on the Isle of Man. Two names, two ways of seeing the same stone.

Ask anyone in Townsville about Castle Hill and they will tell you they have walked it, driven it, or watched the sun come up from it. A bitumen road winds 2.6 kilometres from the northeastern slopes to the Hynes Lookout, perched on the second of the summit's three peaks. From up here the city unspools below, Cleveland Bay opens out, and Magnetic Island floats on the horizon like a green afterthought. Roughly three hundred plant species cling to the thin lithosol soils and bare rock. The surface is so exposed that the hill reads almost as a single piece of stone from a distance. Joggers grind up the road at dawn; visitors linger at dusk. It is less a tourist attraction than a civic ritual.

Look at the northern cliff face and you will spot a stick figure with a halo, painted enormous across the granite: 'The Saint', the logo of the Simon Templar character, daubed there by an unknown hand and stubbornly maintained for decades as a piece of Townsville folklore. The hill carries other marks of human use. Water reservoirs and three radio masts crown the summit, serving aviation, police, ambulance and emergency services. On the northernmost peak squats a low concrete bunker, an observation post built in 1942, when Townsville was a forward base bracing against the threat of Japanese attack and lookouts scanned the sea from this natural watchtower.

There is one more monument here, and its journey was an odd one. Robert Towns, the Sydney merchant whose name the city bears, died in 1873 and was buried in Balmain. He never actually lived in Townsville. When his Sydney cemetery was cleared for parkland in 1940, his memorial was offered to the Townsville council, and not everyone wanted it; one councillor argued Towns had done nothing for the place and that the city carried his name by sheer luck. The truth is harder still. Towns's fortune was built partly on the labour of South Sea Islander men and women, recruited from Pacific islands under coercion and sometimes outright kidnapping to work his Queensland cotton ventures. The monument sat in storage for years before being placed atop Castle Hill in 1949, where it still stands, a marker as complicated as the man it remembers.