Was Katz's deli founded in 1888? Not quite...

From "The Tourists's Guide to Lost Yiddish New York City" (https://sunypress.edu/Books/T/The-Tourist-s-Guide-to-Lost-Yiddish-New-York-City)

The 1903 Sanborn fire map shows a somewhat different business at 210 East Houston Street where Katz's delicatessen is supposed to have been.                                         

Katz’s enjoys bragging rights as the oldest Jewish delicatessen in New York (ergo, the world). Its founding goes back to the Iceland brothers Herman/Hyman (1882–1955) and Morris (ca. 1886–1964). Federal and state census records from 1905 and 1910 of the Icelands (alternately spelled “Island” and “Eisland”) show they arrived in the United States ca. 1900, with the 1905 census showing both brothers working at delicatessens.

By 1910, William Katz (b. Zev Wolf Katz, 1889–1943), who first arrived in the US in 1905,

was Hyman Iceland’s boarder and delicatessen employee. The 1915 New York City directory listing at 207 East Houston Street of “Eisland and Katz” showed Katz was no longer an employee but a partner. (Katz's would move across the street to its present location around 1931 due to subway construction widening Houston Street.) After Katz took over in 1917, and enshrined his name on the business, the Iceland brothers left the restaurant business: Hyman would go into real estate and Morris moved to Saratoga Springs in 1920 and ran a series of kosher hotels.

Katz’s appeared never to have been kosher, unlike its better, down the street competitor Henry’s Delicatessen, but, while Katz’s may never have been kosher, it was, at one time, a union shop. A July 1918 notice in the Forverts announced that William Katz had complied with all union demands and Katz’s would now sport a union placard in its window. Katz would retain his union affiliations into the 1920s as a founding charter member of the Delicatessen Counterman’s Union Local 302. But like the kosher designation, Katz’s would do without the union too. 

Katz’s claims its founding year as 1888. As noted, the Iceland brothers (the acknowledged founders) only arrived in America around 1900, about a  decade after the delicatessen’s supposed 1888 opening. The 1903 Sanborn Fire Map (the bible of insurance company maps) identifies the business where Katz’s should have been, not as a delicatessen, but a Chinese laundry.

None of Katz’s interwar-years newspaper ads give an opening date, and a 1940 New York City tax photo of Katz’s exterior back wall (taken from an empty lot on Orchard Street) shows extensive hand-painted advertising  but no founding date.

The first documented “since” date is in Katz’s 1943  Manhattan phone directory display ad, where it is given as 1900.      

Sometime in the 1950s, the founding date was changed again when brown and tan baked enamel signs were installed on the delicatessen’s Ludlow Street side, with the vertical panel now moving the date back two years to read “since 1898,” at some point  later clumsily rendered into 1888.                                                                  

The earliest print appearance of 1888 as the founding occurs  in an enthusiastic April 25, 1961 Craig Claiborne review ("Meal Is Anytime at Delicatessen") and is no doubt the source of enshrining the incorrect year as the lead line of many subsequent reviews (Internet searches for “Katz’s delicatessen/1888” and “Katz’s deli/1888” net nearly fifty thousand hits.)

  But as “Send a salami to your boy in the Army” was a memorable slogan from Katz’s wartime generation, it was joined by another memorable phrase in 1989: “I’ll have what she’s having,” as Katz’s (in a very strong supporting role) was the setting for that line in the wildly successful 1989 Rob Reiner rom-com When Harry Met Sally. (the scene was recreated in a 2025 Super Bowl ad, for of all things, mayonnaise which, like butter, will never be found in a Jewish delicatessen.) The movie assured not only the delicatessen’s film immortality but likely its business immortality: in 2015 Katz’s sold the air rights above its low-slung restaurant for $17 million, thus ensuring Katz’s location on its own terms in perpetuity no matter. what year it was founded.

Kudos to culinary food writer Robert F. Moss whose 2017 blog posting on Katz's founding date I came across while doing my research, confirming my findings https://www.robertfmoss.com/features/How-Old-is-Katzs-Deli