856 is the telephone area code for southwestern New Jersey, including Haddonfield.
Telephone users in the 856 area making calls to numbers within the 856 area need use only a seven-digit number – example: 555-1212.
Users outside the 856 area making calls to numbers in the 856 area must include the area code – example: 856-555-1212.
Increasing demand by businesses in the late 1990s for phone numbers for telephones, fax machines, and pagers, and by all users for cell phone numbers, made it necessary to split New Jersey's 609 area code in two. 609 was retained for southeastern and central New Jersey, while 856 was introduced for southwestern New Jersey. The change went into effect on June 12, 1999.