It's commonly accepted that Grant had the most corrupt administration in American history, but how much of this reputation is earned? How corrupt were they compared to their contemporaries and near contemporaries?
I don't think it's the last word on the subject. But I answered a similar question here.
19th c. American politics could certainly be corrupt by our standards- elections were often not what you'd call free and fair, and until the Civil Service was created, the patronage or "spoils" system of hiring government employees was very vulnerable to corruption.. But Grant's administration was pretty special even by period standards- like when his brother-in-law Abel Corbin was used by Jay Gould to try to corner the gold market, in the the famous Black Friday stock market panic.