The Lower Mainland is an area in the southwest of British Columbia, Canada, surrounding the city of Vancouver. It is difficult to find an exact definition of the boundries of the region, however the Realty Board generally refers to the following area as being within the Lower Mainland:

North to Pemberton, including the Sunshine Coast, Whistler, and Squamish
West to the Pacific Ocean, sometimes including the Gulf Islands, but not Vancouver Island
East to Chilliwack
South to the United States border

Most of the Lower Mainland is in the 604 area code, however some places have been moved into the relatively new 250 area code which also covers the rest of the province.