On 1 Jan 2004 De Lier merged with Naaldwijk,
en Wateringen, to form the new municipality
Number of inhabitants (1 Jan 2003): 11.400; area: 8,93 km². Settlements:
De Lier (seat)
On 14 Apr 1965 the municipal council of De Lier adopted this flag.
It consists of the colors of the municipal Coat of Arms, with a horizontal center
blue wavy stripe, which symbolizes the old river De Lee, after which De
Lier was named.