The boundaries of Kensington are not well-defined; in particular, the southern part of Kensington has conflicting and complex borders with Chelsea (another ancient manor) whether electoral or postal definitions are used, and has similar architecture. To the west, a border is clearly defined by the line of the Counter Creek marked by the West London railway line. To the north, the only obvious border line is Holland Park Avenue, to the north of which is the district of Notting Hill (another ancient manor), usually classed as within "North Kensington".