River Colne, Hertfordshire in the context of "Colnbrook"

Middlesex (/ˈmɪdəlsɛks/ ; abbreviation: Middx) was one of the counties of England until it was abolished in 1965. The county boundaries largely followed three rivers: the Thames in the south, the Lea to the east and the Colne to the west, with a line of hills forming its northern boundary with Hertfordshire. The former area of Middlesex now lies almost entirely in the ceremonial county of Greater London, with smaller parts in the counties of Hertfordshire and Surrey. The county was the second smallest of the historic counties of England, after Rutland.

The name of the county derives from its origin as a homeland for the Middle Saxons in the early Middle Ages, with the county subsequently part of that territory in the ninth or tenth century. The City of London, formerly part of the county, became a self governing county corporate in the twelfth century; the City was still able to exert influence as the sheriffs of London maintained their jurisdiction in Middlesex, though the county otherwise remained separate. To the east of the City, the Tower Division (or Tower Hamlets) had considerable autonomy under its own Lord Lieutenant. To the west, precincts around Westminster and Charing Cross became built up.

Staines-upon-Thames, commonly known simply as Staines, is a market town in northwest Surrey, England, around 17 miles (28 kilometres) west of central London. It is in the Borough of Spelthorne, at the confluence of the River Thames and Colne. Historically part of Middlesex, the town was transferred to Surrey in 1965. Staines is close to Heathrow Airport and is linked to the national motorway network by the M25 and M3. The town is part of the Greater London Built-up Area.

The earliest evidence of human activity in the area is from the Paleolithic and, during the Neolithic, there was a causewayed enclosure on Staines Moor. The first bridge across the Thames at Staines is thought to have been built by the Romans and there was a settlement in the area around the modern High Street by the end of the 1st century CE. Throughout the Middle Ages, Staines was primarily an agricultural settlement and was held by Westminster Abbey. The first surviving record of a market is from 1218, but one may have taken place near St Mary's Church in the Anglo-Saxon period.

Watford (/ˈwɒtfərd/ ) is a town and non-metropolitan district with borough status in Hertfordshire, England, 16 miles (26 km) northwest of Central London, on the banks of the River Colne.

Initially a small market town, the Grand Junction Canal encouraged the construction of paper-making mills, print works, and breweries. While industry has declined in Watford, its location near London and transport links have attracted several companies to site their headquarters in the town. Cassiobury Park is a public park that was once the manor estate of the Earls of Essex.

Ashford is a town in the Borough of Spelthorne in Surrey, England. The town lies 15 mi (24 km) west of central London. Its name derives from a crossing point of the River Ash, a distributary of the River Colne. Historically part of Middlesex, the town has been part of Surrey since 1965. Ashford consists of relatively low density low- and medium-rise buildings, none of them being high rise. If excluding apartments (at the last census 27% of the housing stock) most houses are semi-detached. In 2011 it had a population of 27,382.

Ashford railway station, on the Waterloo–Reading line, is served by South Western Railway. Heathrow Airport is 2.5 mi (4 km) north of the town.