The Circle Line of the London Underground

Introduction to the Circle Line

The Circle Line is one of the most iconic and instantly recognisable lines on the London Underground, known for its distinctive yellow colour on the Tube map and its almost circular route around Central London.

Despite its name, the line is not a perfect circle, but it plays a crucial role in connecting major rail termini, landmarks, business hubs, and tourist attractions across the city. For both Londoners and visitors alike, the Circle Line offers a comprehensive glimpse into the heart of the capital.

Geography and Route

The Circle Line loops through Central London in a roughly circular shape, forming a ring between Hammersmith in the west and Edgware Road, then looping clockwise via King's Cross, Liverpool Street, and Victoria.

The full route stretches from Hammersmith to Edgware Road via a clockwise circuit through the City of London and Westminster. This makes it unique as a line that both loops and extends beyond its starting point.

Painting of Aldgate Station of the London Underground

Length and Usage

The total length of the Circle Line is approximately 17 miles (27.2 kilometres). Although it was once a closed loop, the extension to Hammersmith in 2009 made it more of a spiral.

Passenger usage of the Circle Line is significant. Pre-pandemic figures (2019) recorded over 114 million journeys annually, placing it among the more moderately used lines. Its usage reflects its importance for interchanging rather than being a primary commuter route from outer suburbs.

History of the Circle Line

The Circle Line has one of the oldest histories in the London Underground system. It was originally formed by connecting two separate railway companies in the 19th century:

The Metropolitan Railway (opened in 1863)
The District Railway (opened in 1868)

These two railways eventually linked up to form a loop around Central London by 1884, often referred to as the "Inner Circle." It was one of the world's first sub-surface urban railway lines.

The line was officially designated the "Circle Line" in 1949, when it was assigned its own identity and yellow colour on the Tube map.

How the Circle Line Got Its Name

As the name suggests, the Circle Line was so named due to its roughly circular route through Central London. The term “Inner Circle” had long been used informally to refer to the loop formed by the Metropolitan and District Railways.

In 1949, this route was officially separated as its own line and named the Circle Line by London Transport. It was given a yellow colour on the Tube map and operated as a continuous loop until 2009, when the western spur to Hammersmith was added to improve reliability.

Stations on the Circle Line

The Circle Line currently serves 36 stations in total. Of these, many are major interchange stations, allowing smooth transfers to nearly every other London Underground line, as well as National Rail services.

Hammersmith Tube Station (Travelcard Zone 2) is an interchange with the Hammersmith & City Line.
Goldhawk Road Tube Station (Travelcard Zone 2) is an interchange with the Hammersmith & City Line.
Shepherd's Bush Market Tube Station (Travelcard Zone 2) is an interchange with the Hammersmith & City Line.
Wood Lane Tube Station (Travelcard Zone 2) is an interchange with the Hammersmith & City Line.
Latimer Road Tube Station (Travelcard Zone 2) is an interchange with the Hammersmith & City Line.
Ladbroke Grove Tube Station (Travelcard Zone 2) is an interchange with the Hammersmith & City Line.
Westbourne Park Tube Station (Travelcard Zone 2) is an interchange with the Hammersmith & City Line.
Royal Oak Tube Station (Travelcard Zone 2) is an interchange with the Hammersmith & City Line.
Paddington Tube Station is a central London train terminus and London Underground station. It is also the terminus of the Heathrow Express. The Paddington Tube Station (Travelcard Zone 1) is an interchange with the Bakerloo Line, District Line, Hammersmith & City Line.
Edgware Road Tube Station are actually two different stations with the same name. The Circle line interchanges with District and Hammersmith & City Lines with the same station, while 150 meters away is another Edgware Road tube station served by only the Bakerloo line. The Edgware Road Tube Station (Travelcard Zone 1) is an interchange with the District Line and Hammersmith & City Line.
Baker Street Tube Station is actually three different stations with the same name. The station for Circle Line and Hammersmith & City Line is between Great Portland Street and Edgware Road. Between Great Portland Street and Finchley Road is another station, for the Metropolitan Line, while between Regent's Park and Marylebone Tube Station, between Bond Street and St John's Wood is the Baker Street Tube Station for the Jubilee Line. The Baker Street Tube Station (Travelcard Zone 1) is an interchange with the Hammersmith & City Line.
Great Portland Street Tube Station (Travelcard Zone 1) is an interchange with the Hammersmith & City Line and Metropolitan Line.
Euston Square Tube Station is a different station from the nearby Euston tube station. It is within walking distance of the Euston railway station. The Easton Square Tube Station (Travelcard Zone 1) is an interchange with the Hammersmith & City Line and Metropolitan Line.
King's Cross St Pancras Tube Station serves both the King's Cross and St Pancras railway stations. This is the biggest interchange Tube Station for the London Underground, served by six underground lines on its four pairs of tracks. The King's Cross St Pancras Tube Station (Travelcard Zone 1) is an interchange with the Hammersmith & City Line, Metropolitan Line, Northern Line, Piccadilly Line and Victoria Line.
Farringdon Tube Station is a London Underground and National Rail station. The Farringdon Tube Station (Travelcard Zone 1) is an interchange with the Hammersmith & City Line and Metropolitan Line.
Barbican Tube Station (Travelcard Zone 1) is an interchange with the Hammersmith & City Line and Metropolitan Line.
Moorgate Tube Station is a London Underground and National Rail station. The Moorgate Tube Station (Travelcard Zone ) is an interchange with the Northern Line, Hammersmith & City Line and Metropolitan Line.
Liverpool Street Tube Station is a central London railway terminus served by the London Underground. It is the London terminus of the Great Eastern Main Line to Norwich and the West Anglia Main Line to Cambridge. The Liverpool Street Tube Station (Travelcard Zone 1) is an interchange with the Central Line, Hammersmith & City Line and Metropolitan Line.
Aldgate Tube Station (Travelcard Zone 1) is an interchange with the District Line, Hammersmith & City Line and Metropolitan Line.
Tower Hill Tube Station (Travelcard Zone 1) is an interchange with the District Line.
Bank-Monument Tube Station two stations joined as one, with different entrances bearing different names. The Bank and Monument stations are served by five London Underground lines and the Docklands Light Railway. They were named after the Bank of England and the Monument to the Great Fire of London. The Bank-Monument Tube Station (Travelcard Zone 1) is an interchange with the Central Line, Northern Line, District Line and Waterloo & City Line.
Cannon Street Tube Station is a central London railway terminus and London Underground station within the City of London, in the financial district of London. The Cannon Street Tube Station (Travelcard Zone 1) is an interchange with the District Line.
Mansion House Tube Station (Travelcard Zone 1) is an interchange with the District Line.
Blackfriars Tube Station is a London Underground and National Rail station. It is presently closed for refurbishment until 2011. The Blackfriars Tube Station (Travelcard Zone 1) is an interchange with the closed.
Temple Tube Station (Travelcard Zone ) is an interchange with the District Line.
Embankment Tube Station (Travelcard Zone ) is an interchange with the Bakerloo Line, District Line and Northern Line.
Westminster Tube Station (Travelcard Zone 1) is an interchange with the District Line and Jubilee Line.
St James's Park Tube Station (Travelcard Zone 1) is an interchange with the District Line.
London Victoria Tube Station is a major central London railway terminus, along with a London Underground station and a coach station. It is the busiest station on the London Underground system and the second busiest railway terminus in London after the London Waterloo station. This is the London terminus for the Chatham Main Line to Keng, and the Brighton Main Line to Surrey, Sussex, Gatwick Airport and Brighton. It is also the terminus for the Venice Simplon Orient Express. The London Victoria Tube Station (Travelcard Zone 1) is an interchange with the District Line and Victoria Line.
Sloane Square Tube Station (Travelcard Zone 1) is an interchange with the District Line.
South Kensington Tube Station (Travelcard Zone 1) is an interchange with the District Line and Piccadilly Line.
Gloucester Road Tube Station (Travelcard Zone 1) is an interchange with the District Line and Piccadilly Line.
High Street Kensington Tube Station (Travelcard Zone 1) is an interchange with the District Line.
Notting Hill Gate Tube Station (Boundary of Travelcard Zones 1 and 2) is an interchange with the Central Line and District Line.
Bayswater Tube Station (Travelcard Zone 1) is an interchange with the District Line.

Neighbourhoods and Areas Served

The Circle Line connects a wide range of London's most significant districts, offering excellent accessibility to:

Hammersmith – a busy commercial and entertainment district
Paddington – with connections to Heathrow via the Heathrow Express
Bayswater and Notting Hill – trendy and residential West London areas
King’s Cross – a major transport hub and redevelopment hotspot
The City of London – London's historic and financial core
Westminster – home to Parliament, Big Ben, and Whitehall
South Kensington – the museum district including the V&A and Natural History Museum

This wide coverage makes the Circle Line popular with tourists seeking to explore London’s major sights.

Major Interchange Stations

The Circle Line is invaluable for changing between other lines and national services. Notable interchanges include:

King’s Cross St. Pancras – connections to the Northern, Victoria, Piccadilly, Hammersmith & City, and Metropolitan lines, plus Eurostar and national rail
Paddington – Bakerloo, District, and Hammersmith & City lines, and National Rail
Victoria – Victoria and District lines, and National Rail
Liverpool Street – Central, Metropolitan, Hammersmith & City lines, and national rail services
Moorgate – connections to Northern and Metropolitan lines and mainline trains
Embankment – Bakerloo and Northern lines

These interchanges make the Circle Line an essential part of the Underground’s connective tissue.

Fun Fact: A Circular Line That's Not a Circle

Despite the name, the Circle Line is no longer a true loop. Until 2009, it operated as a continuous circuit with no terminal station. However, this design led to poor reliability, as delays would compound around the circle. To solve this, in 2009, the line was extended westward to start at Hammersmith, creating a spiral-like route with a definitive beginning and end. The change improved punctuality and allowed more frequent service. Another fun detail: although originally designed to go entirely underground, parts of the Circle Line run above ground, especially on the western end toward Hammersmith.

Why the Circle Line Matters

For many Londoners and visitors, the Circle Line is the “glue” of the Tube network – connecting major rail termini, business hubs, and cultural hotspots. While not the fastest line for point-to-point journeys, its unique role in looping around the city makes it highly practical. For tourists, it offers an easy route to some of the city’s top attractions without needing to navigate deep-level Tube stations.

Conclusion

The Circle Line is more than just a line on the map—it is a journey through London’s history, geography, and modern infrastructure. Whether you're commuting across the city or sightseeing, the Circle Line offers a distinct perspective on Central London. Its central role, historical roots, and expansive reach make it a vital thread in the fabric of London life.