1880
The oldest U.S. census records I could find were for Sam and Minnie, both in Manhattan, NYC in 1880 a few years before they married.
Sam
Minnie
1900
Since the 1890 census was destroyed the next one to search was 1900, where I found the whole clan, except Zeppo, who wasn’t born until 1901.
Pauline was a Marx cousin, daughter of Minnie’s sister, Hannah.
1905
In 1905 there was a state (as opposed to a federal) census in New York. Sam is a mystery. Maybe a relative of Frenchie. And Grandpa Louis (“Lafe”) Schoenberg is recorded as “Nathan.”
1910
They were all together in 1910 also, at 4649 Calumet Ave. in Chicago, IL. Except for Chico who was working in Philadelphia.
Above on the page are Aunt Hannah (“Anna”) and her husband, Uncle Julius Schickler.
1917
Though not census information, this seems a good place to record their World War I draft cards.
Chico in Chicago.
Harpo on the farm.
Groucho in Chicago.
Gummo on the farm.
1920
In 1920 they all proved devilishly hard to find. Except Chico and Gummo, who were both living in Manhattan.
Chico
Gummo
As for Sam, Minnie, Harpo, and Zeppo, my best guess is that they were on the road after selling the Chicago house (they’re not enumerated there) and before having official residence in New York, so fell between the census cracks.
1930
By 1930 Minnie had died and the boys had married and scattered.
Sam was still living in Manhattan.
As was Chico. Living alone as a theatrical manager.
Gummo was in Manhattan and is using the name “Gummo.”
Groucho was in Great Neck.
Zeppo was living at 169 East 78th St. in Manhattan in 1930, though he was not enumerated there in the 1930 census.
Minnie died at that address in 1929, and Zeppo reported it as his address when he sailed into New York harbor in February 1931.
1940
By 1940 they had all landed in Los Angeles.
Chico
Harpo (as Arthur)
Groucho (as Julius)
Gummo
Zeppo
His $50,000 house is the most expensive of the brothers.
And since we’re tracking Marxes in the draft, here are their 1942 World War II draft cards.
Chico
Harpo
Groucho (as “Groucho Henry Marx”)
Gummo (as “Milton Gummo”, employed by Zeppo.)
Zeppo (from the WW II Young Men’s Draft)
1950
In 1950 all the brothers were enumerated in California.
Chico living alone (and separated) in an undistinguished section of Beverly Hills. at 409 1/2 Spalding.
He didn’t work in the last week, wasn’t looking for work, but had a job as “motion picture comedian.”
Also, he’s named at “Leo Chico Marx,” the only one of the brothers in this census with a real name mention.
Harpo and Gummo enumerated sequentially but actually living about a half a mile apart.
Harpo at 701 North Canon Drive, Beverly Hills, and Gummo at 601 North Beverly Drive.
Groucho at 806 North Foothill Drive, Beverly Hills.
His age is off by three years, but maybe you shade down if you’re married to a 26 year old (her correct age).
Apart from the cook and the upstairs maid a Virginia Semon in enumerated as “cousin-in-law.” She’s the daughter of Kay’s maternal aunt Marie (Hodgson) Semons.
Zeppo at 1001 Rexford, Beverly Hills.
He worked 40 hours the previous week in “airplane parts manufacturing.”
Happily, his line was one where they collected extra info.
Father’s place of birth had “Germany” crossed out and “Alsace-Lorraine” written in. He worked 50 weeks in 1949. Finished the 8th grade.
No income reported, but they noted that they left an income form.
And for good measure, Arthur Marx, living with his mother-in-law Grace Kahn, and Margaret Dumont living as a lodger.
From The Marxives 