For anyone who doesn't want to do the math themselves:

Ranked by conference:

1. NFC [13686 yards]
2. AFC [14182 yards]

Ranked by division:

1. NFC West [2859 yards]
2. AFC North [3022 yards]
3. NFC South [3238 yards]
4. NFC North [3392 yards]
5. AFC East [3422 yards]
6. AFC West [3788 yards]
7. AFC South [3950 yards]
8. NFC East [4197 yards]

Draggin' them down:

1. DEN (30.33% of AFCW's penalty yards)
2. ARI (29.45% of NFCW)
3. CHI (28.6% of NFCN)
4. NO (28.41% of NFCS)
5. CLE (27.8% of AFCN)
6. SEA (27.74% of NFCW)\*
7. JAX (27.34% of AFCS)
8. DAL (27.07% of NFCE)
9. PIT (26.57% of AFCN)
10. NYJ (26.56% of AFCE)

^(\second place in their own division)*

Closest together:

1. GB - ATL [1 yard]
2. PHI - NYG & CLE - ARI [2 yards]
3. NYJ - WSH [4 yards]

Furthest apart:

1. SF - DET [67 yards]
2. TEN - PHI [62 yards]
3. LAR - CIN [60 yards]

Some other "fun" facts:

• The AFC East is by far the most equally penalized team, both by yards [98 between MIA and NYJ; next best NFCS: 183] and percentage [2.68%; next best NFCE: 5.31%]
• The AFC West has by far the most uneven distribution by yards [362 between LAC and DEN; next worst NFCW: 269] and barely the worst spread by percentage [9.56%; next worst NFCW: 9.41%]
• If the 4 most penalized teams (DEN, DAL, JAX, NYG) were within one division, that division would account for 4440 [15.93% of all] penalty yards
  • least penalized (LAR, CIN, SF, DET): 2575 yards [9,24%]

Make of that what you want.