This is where all tenure-stream faculty (junior and senior) at the PGR top 20 programs for 2017-18 earned their PhDs. Remember that Harvard and Princeton were the top departments in the country from the mid-1950s through the 1980s (Harvard for much longer than that before, though Harvard declined more than Princeton in the 1990s); in the 1990s, first Rutgers, then NYU emerged as dominant programs. MIT's PhD program began in the early 1960s, and was a top ten program from the start (early faculty included Hilary Putnam and John Rawls); Pittsburgh emerged as a philosophy powerhouse in the early 1960s as well. Michigan had a top ten, often top five, PhD program from the 1950s onwards. UCLA emerged in the 1950s (first with Hans Reichenbach, then Rudolf Carnap, Richard Montague and others) as a major PhD program, while Berkeley became a more prominent player in the field in the 1960s. Yale went from top ten status in the 1950s, through many years of conflict and decline, before reemerging in the 1990s as a major PhD program. Cornell was one of the top ten programs from the 1950s until the early 1990s. Columbia, like Yale, had ups and downs, sometimes in the top ten, sometimes not even in the top twenty. Chicago was a solidly top ten program during the time Donald Davidson was on the faculty (1976-1981), and a top 15-20 program most of the rest of the time. Stanford has been a top ten program since the 1960s, with Patrick Suppes and a young Donald Davidson, among others.
Programs are ranked by the total number of graduates in tenure-stream positions in the current U.S. top twenty, though I also note the number of those faculty who are untenured but on tenure-track; in ten years time, Rutgers and NYU will be giving Harvard and Oxford a run for the money (probably Berkeley too).
1. Princeton University (55 total, 7 currently junior)
2. Harvard University (43 total, 4 currently junior)
3. Massachussetts Institute of Technology (31 total, 5 currently junior)
4. Oxford University (24 total, 3 currently junior)
4. University of California, Berkeley (24 total, 7 currently junior)
6. University of Pittsburgh (Philosophy & HPS) (23 total, 1 currently junior)
7. Rutgers University, New Brunswick (22 total, 7 currently junior)
8. Yale University (18 total, 4 currently junior)
9. New York University (16 total, 8 currently junior)
9. Stanford University (16 total, 1 currently junior)
11. University of Michigan, Ann Arbor (15 total, 2 currently junior)
12. University of Chicago (13 total, 1 currently junior)
13. University of California, Los Angeles (12 total, 1 currently junior)
14. Columbia University (11 total, 3 currently junior)
14. Cornell University (11 total, 1 currently junior)
Among other programs we looked at, we found 5 Arizona PhDs in top 20 departments (three at Arizona, none junior), 4 Brown PhDs (none junior), 5 Texas PhDs (1 junior), 4 UC San Diego PhDs (none junior), 3 Penn PhDs (none junior) and 6 Notre Dame PhDs (five at Notre Dame, none junior).
We didn't look at Cambridge or Toronto PhDs, but I strongly suspect they would have done at least as well as the preceding programs.