Northern Sydney comprises a dynamic mix of neighborhoods, including the Upper North Shore, Lower North Shore, and the Northern Beaches. This region boasts notable landmarks such as Macquarie University, Gladesville Bridge, Ryde Bridge, the bustling Macquarie Centre, and Curzon Hall in Marsfield. It falls under the jurisdiction of local government areas, including Hornsby Shire, Ku-ring-gai Council, the City of Ryde, the Municipality of Hunter's Hill, and parts of the City of Parramatta.

At the heart of Northern Sydney, North Sydney and Chatswood stand out as major commercial hubs. North Sydney is home to a significant concentration of high-rise buildings, making it the second-largest commercial district in Sydney after the CBD. The area is dominated by advertising, marketing, and associated industries, with numerous large corporations establishing their offices here. Chatswood is known for its diverse shopping and dining options, attracting both locals and tourists.

The Northern Beaches area, which includes popular destinations like Manly, has long been favored for its stunning coastline and recreational opportunities. The region is characterized by picturesque headlands that mark the entrance to Sydney Harbour, extending south to Port Jackson, west to Middle Harbour, and north to Broken Bay. According to the 2011 Australian census, the Northern Beaches was identified as one of the most homogenous districts in Australia, in contrast to the more diverse populations of the North Shore and Central Coast.

As of the end of 2021, Northern Sydney was notable for its real estate market, with half of the top 20 most expensive postcodes in Australia (based on median house prices) located in this area. This includes four postcodes on the Northern Beaches, two on the Lower North Shore, three on the Upper North Shore, and one that straddles Hunters Hill and Woolwich.

Additionally, the Hills District, situated in north-western Sydney, features a unique hilly landscape characterized by the transition from the Cumberland Plain to the Hornsby Plateau. This district encompasses various suburbs under the Hills Shire local government area and parts of the City of Parramatta Council and Hornsby Shire. The Hills District Historical Society defines the region's boundaries, although its study area stretches from Parramatta to the Hawkesbury. Key thoroughfares like Windsor and Old Windsor Roads hold historical significance as some of the earliest roads constructed in Australia.

Overall, Northern Sydney presents an appealing blend of luxury living, commercial vibrancy, and natural beauty, making it a sought-after destination for residents and visitors alike.