ive been trying to find this but the great depression was the main story form back then so its kinda hard to find anything about the rich people.
ouch rachel but thx for the answer...
The Rockefellers were almost certainly the richest family.
#2 probably would have been the Morgans or the Duponts, who had expanded their already huge fortunes during the profiteering of WWI. The ultra-rich tended to keep the true extent of their fortunes hidden, much as they do now, where it's estimated that less than 1% of the population owns 50% of the wealth in the USA.
Incidentally, if you're looking for a fascinating and little-known depression-era story, here you go.