Newcastle is strategically located on the southern bank of the Hunter River mouth, offering picturesque coastal views and an intriguing geography. The northern side of the river is defined by sand dunes, swamps, and numerous river channels, creating a natural barrier to urban development. The city's "green belt," which protects local plant and wildlife, stretches from the west through the Watagan Mountains and curves around to the north, where it meets the coastline just north of Stockton.

The urban landscape of Newcastle is largely concentrated on the hilly southern bank, with much of the area underpinned by the coal measures of the Sydney sedimentary basin. Historically, many coal-mining villages were scattered throughout the hills and valleys around the port, but over time these communities have merged into the single metropolitan area we know today, extending southward to Lake Macquarie. To the north and south, Newcastle is bordered by the Mid North Coast and Central Coast regions, while neighboring Hunter local government areas lie to the west and northwest.

Across the river, the small town of Stockton sits at the mouth of the Hunter River, connected to central Newcastle by a ferry service and the Stockton Bridge, located approximately 20 kilometers away. The natural beauty of the surrounding areas, including the river and coastal landscapes, combined with urban development, provides a balanced living environment for the city’s residents.

Newcastle is home to several parks that enhance its natural appeal. King Edward Park, established in 1863, offers stunning coastal views and features a sunken garden and a Victorian rotunda. Another beloved green space, Starrett Park in New Lambton, is known for its lush grass and vibrant playground. These parks, among others, provide locals and visitors alike with a chance to enjoy the outdoors while appreciating the city’s unique geographic setting.