The Philadelphia district has an amazing collection of par 3s somewhat do to Flynn's predilection for designing outstanding par 3s. But the short par 4s (and long par 4s and all sorts of par 5s as well) in the district merit consideration as well.
Merion's collection of short par 4s is hard to top anywhere: 1,7,8,10 and 11. Can they be beat?
Pine Valley's short par 4s: 2,8,12 and 17. These 4 the equal of Merion's 5 short par 4s? Maybe.
Other Philadelphia courses to consider:
Merion West: 1,7,8,10,12,13 and 18
Rolling Green: 4,5,12 and 15
Philadelphia Country: 1,2 13 and16
Lehigh Country Club: 2,4,14 and 15
Lancaster Country Club: 2 and 16
Huntingdon Valley: 1(plays short),4 and 11
Atlantic City Country Club: 2,3 and Doak's 14th
French Creek: 1,7 and 14
Manufacturers: 1 and 17
LuLu: 2,9,11,14 and 16
Philadelphia Cricket Club: 5 and 6
Bidermann: A lot of short par 4s, maybe not great but solid including 1,5,7,9,13,17
Gulph Mills: 5,8,9,11 and 15
Whitemarsh Valley: not great but solid including 1,10 and 14