Peripatetiapolis is a Traction City which appears in Mortal Engines and A Darkling Plain. It is 4 tiers high and roams in the Great Hunting Ground. Its mayor is unknown.

In Mortal Engines, Tom, Hester, and Anna Fang briefly stop at Peripatetiapolis while flying the Jenny Haniver to Batmunkh Gomba. The citizens of the city warn them that Thaddues Valentine's airship, the 13th Floor Elevator is flying near Shan Guo. They then leave the city continue their journey.

At the beginning of A Darkling Plain, Tom and his daughter Wren are at Peripatetiapolis, and Tom visits a doctor and finds out that the bullet which Nimrod Pennyroyal shot into him in Anchorage will eventually kill him. Clytie Potts (under the identity of Cruwys Morchard), a former Historian of London, arrives at Peripatetiapolis to buy supplies for the surviving Londoners, and Kliest Coils for the construction of New London.