Since people are posting about big locations here. I help maintain Pinball Map. Here's a query of locations in the US, sorted by number of machines. Limited to places with 60+. Not sure how well this will be formatted...

name | city | state | country | count

-----+------+-------+---------+-------

Pinball Hall of Fame | Las Vegas | NV | US | 337

Pinball Perfection | Westview | PA | US | 311

Next Level Pinball Museum | Hillsboro | OR | US | 242

Pinball PA | Aliquippa | PA | US | 176

Game Galaxy | Smyrna | TN | US | 169

Wizard's World | Fort Wayne | IN | US | 144

District 82 Pinball | De Pere | WI | US | 114

Pacific Pinball Museum | Alameda | CA | US | 106

Game Terminal | Nashville | TN | US | 105

Silverball Retro Arcade | Asbury Park | NJ | US | 100

ElectroMagnetic Pinball Museum | Pawtucket | RI | US | 96

The Pinball Palace | Brunswick | GA | US | 92

Pocketeer Billiards and Bar | Buffalo | NY | US | 85

Pinballz Arcade | Austin | TX | US | 83

Recbar 812 | New Albany | IN | US | 80

Pinball Gallery | Malvern | PA | US | 79

Grumpy's Arcade | Glendale | AZ | US | 77

Silverball Retro Arcade | Delray Beach | FL | US | 75

CP Pinball | South Roxana | IL | US | 74

Idaho Pinball Museum | Garden City | ID | US | 73

Pinball Long Island | Patchogue | NY | US | 73

Recbar | Louisville | KY | US | 71

Clubhouse Arcade | Fremont | MI | US | 68

Crazy Quarters Arcade | Bay City | MI | US | 67

Lucky Snake Arcade & Sports Bar | Atlantic City | NJ | US | 67

Flippers Arcade | Grandy | NC | US | 67

Western Mass Pinball Club | Palmer | MA | US | 65

Roanoke Pinball Museum | Roanoke | VA | US | 65

Replay Museum | Tarpon Springs | FL | US | 65

Captain's Arcade Showroom | Anaheim | CA | US | 65

Pastime Pinball | Manchester Center | VT | US | 64

The Pinball Palace (Dezerland Park) | Orlando | FL | US | 60