How many letters does the top answer for “author of federalist papers” have?

The most common answer is hamilton (8 letters).

Crossword clue: author of federalist papers

2 answers found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

hamilton 8 letters wd-fact-v3

the capital of Bermuda

madison 7 letters wd-fact-v3

capital of the state of Wisconsin; located in the southern part of state; site of the main branch of the University of W

author of paper towns 50% similar → green

author of the pickwick papers 50% similar → dickens

wrote federalist papers 50% similar → hamilton, madison