The area code 224 is the one which stretches covering the major areas of Lake County and the northern regions of Cook County and Kane County. A smaller part of McHenry County is also covered by them. Area code 224 and area code 847 are the part of overlay covering the above mentioned regions. On January 5, 2002 the area code 224 overlaid 847 and then the eleven-digit was introduced in all the covered regions. Area code 847 is also a result of split from the area code 708.

The area code is mentioned in "The Art of the Steal: How to Protect Yourself and Your Business from Fraud" by Frank W. Abagnale regarding a 900 phone call scam. He stated that the 847 area used to be a "premium" phone call area code in the North American Numbering Plan.

The names of some of the important places which are around this particular area are the following:

Algonquin, Antioch, Arlington Heights, Bannockburn, Barrington, Barrington Hills, Beach Park, Buffalo Grove, Burlington, Carpentersville, Cary, Channel Lake, Deerfield, Deer Park, Des Plaines, East Dundee, Elgin, Elk Grove Village, Evanston, Forest Lake, Fox Lake, Fox Lake Hills, Fox River Grove, Gages Lake, Gilberts, Glencoe, Glenview, Golf, Grandwood Park, Grayslake, Green Oaks, Gurnee, Hainesville, Hampshire, Hawthorn Woods, Highland Park, Highwood, Hoffman Estates, Huntley, Indian Creek, Ingleside, Island Lake, Inverness, Kenilworth, Kildeer, Knollwood, Lake Barrington, Lake Bluff, Lake Catherine, Lake Forest, Lake in the Hills, Lake Villa, Lake Zurich, Libertyville, Lincolnshire, Lincolnwood, Lindenhurst, Long Grove, Long Lake, Mettawa, Morton Grove, Mount Prospect, Mundelein, Niles, North Barrington, Northbrook, North Chicago, Oakwood Hills, Old Mill Creek, Palatine, Park City, Park Ridge, Pingree Grove, Port Barrington, Prairie View, Prospect Heights, Riverwoods, Rolling Meadows, Rondout, Rosemont, Round Lake, Round Lake Beach, Round Lake Heights, Round Lake Park, Schaumburg, Skokie, Sleepy Hollow, South Barrington, South Elgin, Third Lake, Tower Lakes, Trout Valley, Venetian Village, Vernon Hills, Volo, Wadsworth, Wauconda, Waukegan, West Dundee, Wheeling, Wilmette, Winnetka, Winthrop Harbor and Zion.