Watford (/ˈwɒtfərd/) is a town and borough in Hertfordshire, England, 15 miles northwest of Central London, on 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 has 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.