Before area codes, there were exchange prefixes in the Chicago telephone system.
When the telephone system began in Chicago in 1892, the caller would connect to the operator and provide them the name of the exchange they wished to call, followed by their contact's assigned specific 3-digit number (ie. Mulberry 666)
Of course, by 1921, so many people had telephones that this format had to be modified. The system became a 3-letter, 4-digit system (ie. MUL-1666). This became a 2-letter, 5-digit system by 1948 (ie. MU5-1666) and by 1977, Chicago had officially done away with this system.
Some exchange prefixes helpfully referred to nearby locations (HArrison for Harrison Street, HUmboldt for Humboldt Park, etc.) although some were just common ones that were used in other cities (SH for SHeldrake, BI for BIttersweet).
You can read more about it in this great article on Forgotten Chicago. In the photo gallery below, you can find a page from the 1941 (3-letter) and 1951 (2-letter) Chicago phone directory that explains it a little more, along with an entire listing of what the old exchanges used to be.
Here is a list of places where old telephone numbers have been spotted in Chicago:
- 9449 S. Halsted Street in Washington Heights. Homecraft Construction still has their vintage signage. VI6-2441. (The VI stood for VIncennes.)
- 230 S. Wabash Avenue in the South Loop. Ghost sign advertising office space in the Steger Building. HA7-555?. (HA stood for HArrison.)
- 222 W. Kinzie Street in River North. Ghost sign for Bartman's behind the building viewable from the Brown Line. MO4-2800. (MO stood for MOhawk)
- 319 W. Ontario Street in River North. Ghost sign. MO4-8383. (MO stood for MOhawk) Here is a photo of the sign when it was still very visible in 1978.
- 416 W. Erie Street in River North. Ghost sign for electronic repair business. DElaware 7-7373.
- 731 N. LaSalle Street in Near North. The LaSalle Flower Shop still has its vintage signage. SU7-3680. (SU stood for SUperior.)
- 820 N. Franklin Street in Near North. Ghost sign for cigar boxes as well as a picture frame company viewable from the Brown Line. DELaware 8136, 8132. Note the 3-digit prefix that dates it before 1948.
- 1030 N. Wood Street in East Village. Ghost sign for Flynn Fence. EStebrook 3-6268.
- 1244 N. Wolcott Avenue in Wicker Park. Ghost sign for RR Work Done Realty. ME7-3215 (ME stood for MErrimac)
- 1533 W. Chicago Avenue in West Town. Ghost sign for Meyer Bros? BA1-5774 (BA stood for BAyport)
- 1562 N. Damen Avenue in Wicker Park. Ghost sign for Don & Sons Roofing. AR6-5026. (AR stood for ARmitage) *This sign is currently obscured.
- 236 W. Willow Street in Old Town. Ghost sign for Clark Roofing & Construction Co. SP2-7410. (SP stood for SPaulding)
- 2100 W. Armitage Avenue in Bucktown. Ghost sign for POLONIaA & Sons Roofing. BE5-4996. (BE stood for BElmont)
- 3122 N. Kedzie Avenue in Logan Square. Illegible ghost sign. IN3-CO??. (IN stood for INdependence)
- 3931 N. Damen Avenue in North Center. Ghost sign for Anderson Brothers Storage. WE5-0013. (The old phone number is now painted over, but the WE stood for WEllington)
- 4397 N. Elston Avenue in Mayfair. Vintage sign for El-Mont Liquors. MUL-1666. (MUL stood for MULberry). Note the 3-digit prefix that dates it before 1948. (Unfortunately, this sign was removed a few years ago.)
- 4570 N. Broadway Street in Uptown. Viewable from the Wilson L stop, another vintage sign for roofing work. JU8-6550. (JU stood for Juniper)
- 4800 W. Irving Park Road in Portage Park. Vintage neon sign for hotel work. SP7-0661. (SP stood for SPring). (This sign has been removed and is now in possession of the Six Corners Association.)
- 6506 W. Belmont Avenue in Dunning. Frank's Pizzeria still has its vintage signage. AV3-2564. (AV stood for AVenue)
- 6161 N. Broadway Street in Edgewater. Ghost sign behind building for a interior decor company viewable from the Red Line. SH3-?111 (SH stood for SHeldrake)
Have you seen a sign with an old telephone prefix that I don't have listed here? Post a comment!