Greenford (ˈgriːnfərd) is a large town in the London Borough of Ealing in west London, England, lying west from Charing Cross. It has a population of 46,787 inhabitants, or 62,126 with the inclusion of Perivale. Greenford is served by Greenford Station (London Underground Central Line and Greenford branch of the Great Western Railway mainline service). South Greenford mainline station (on the A40 Western Avenue, also on the Greenford branch of the GWR) is actually in Perivale. Neither station is in Greenford Town Centre (Greenford Broadway), which instead is served by many local buses. Nearby places include Yeading, Hanwell, Perivale, Southall, Northolt, Ealing, Sudbury and Sudbury Hill. The most prominent landmark in the suburb is Horsenden Hill, above sea level. Greenford covers a large area, including the two miles of Greenford Road, giving it three localities: North Greenford, Greenford Green, and Greenford Broadway – this is also reflected in the names of the electoral wards. Though a separate "town" within the borough of Ealing, the Royal Mail includes Perivale within the Greenford post area and as such the two share the UB6 postcode. The name is first recorded in 848 as Grenan forda. It is formed from the Old English 'grēne' and 'ford' and means 'place at the green ford'. Greenford was known as Great Greenford in order to distinguish it from Little Greenford, which is now known as Perivale (Greenford and Perivale, though different places, still share the UB6 postal code). The affixes 'Magna' and 'Parva' have also been used to denote the difference. Greenford was an ancient parish in the historic Elthorne Hundred, county of Middlesex. Greenford is considered to be birthplace of the modern organic chemical industry, as it was at William Perkin's chemical factory in North Greenford, by the Grand Union Canal, that the world's first aniline dye was discovered in March 1856. Perkin called his amazing discovery 'mauveine'. Today there is a blue plaque marking the spot in Oldfield Lane North, just south of the Black Horse public house.