| KIKermitool, Inc. | York | PA | Machinery Manufacturing333515 | 20-99 | ◐ LIKELY ACTIVE |
| KCKerrico Corporation | Selinsgrove | PA | Plastics and Rubber Products Manufacturing326121 | 1-19 | ◐ LIKELY ACTIVE |
| KFKeystone Filler & Mfg/muncy Coal Prep Pl | Muncy | PA | Nonmetallic Mineral Product Manufacturing327992 | 20-99 | ◐ LIKELY ACTIVE |
| KFKeystone Forging CO | Northumberland | PA | Fabricated Metal Product Manufacturing332111 | 20-99 | ◐ LIKELY ACTIVE |
| KFKeystone Friction Hinge Co | South Williamsport | PA | Fabricated Metal Product Manufacturing332116 | 20-99 | ◐ LIKELY ACTIVE |
| KPKeystone Powdered Metal Co/lewis Run | Lewis Run | PA | Fabricated Metal Product Manufacturing332117 | 100-499 | ◐ LIKELY ACTIVE |
| KPKeystone Powdered Metal CO - St Marys Facility | Saint Marys | PA | Fabricated Metal Product Manufacturing332117 | 100-499 | ◐ LIKELY ACTIVE |
| KSKeystone Screw Corp/willow Grove | Willow Grove | PA | Fabricated Metal Product Manufacturing332722 | 20-99 | ◐ LIKELY ACTIVE |
| KWKeystone Wood Specialties | Lancaster | PA | Wood Product Manufacturing321918 | 20-99 | ◐ LIKELY ACTIVE |
| KCKh Controls INC | Blairsville | PA | Electrical Equipment, Appliance & Component Manufacturing335999 | 20-99 | ◐ LIKELY ACTIVE |
| KMKin-tech Mfg INC | Irwin | PA | Fabricated Metal Product Manufacturing332710 | 1-19 | ◐ LIKELY ACTIVE |
| KFKnouse Foods Coop INC Chambersburg Plant | Chambersburg | PA | Food Manufacturing311421 | 100-499 | ◐ LIKELY ACTIVE |
| KGKorns Galvanizing CO INC | Johnstown | PA | Fabricated Metal Product Manufacturing332812 | 20-99 | ◐ LIKELY ACTIVE |
| KKKountry Kraft | Newmanstown | PA | Furniture and Related Product Manufacturing337110 | 20-99 | ◐ LIKELY ACTIVE |
| LILabchem INC | Zelienople | PA | Chemical Manufacturing325998 | — | ◐ LIKELY ACTIVE |
| LCLamtec CORP | Mount Bethel | PA | Paper Manufacturing322220 | 100-499 | ◐ LIKELY ACTIVE |
| LMLancaster Metal Manufacturing | Lancaster | PA | Fabricated Metal Product Manufacturing332322 | 20-99 | ◐ LIKELY ACTIVE |
| LOLand O'lakes - Carlisle | Carlisle | PA | Food Manufacturing311511 | 100-499 | ◐ LIKELY ACTIVE |
| LTLaser Tool INC | Saegertown | PA | Plastics and Rubber Products Manufacturing326199 | 1-19 | ◐ LIKELY ACTIVE |
Laser-view Technologies INC | Chester Springs | PA | Computer and Electronic Product Manufacturing334513 | 1-19 | ◐ LIKELY ACTIVE |
| LSLebanon Seaboard CORP | Lebanon | PA | Textile Product Mills314911 | 100-499 | ◐ LIKELY ACTIVE |
| LHLehigh Heavy Forge CORP | Bethlehem | PA | Textile Product Mills314999 | 100-499 | ◐ LIKELY ACTIVE |
| LTLite Tech INC | Norristown | PA | Plastics and Rubber Products Manufacturing326113 | 1-19 | ◐ LIKELY ACTIVE |
Lloyd Industries, INC. | Montgomeryville | PA | Fabricated Metal Product Manufacturing332322 | 20-99 | ◐ LIKELY ACTIVE |
| LRLoad Rite Trailers INC | Fairless Hills | PA | Transportation Equipment Manufacturing336214 | 100-499 | ◐ LIKELY ACTIVE |
| LBLucisano Brothers, INC. | Tullytown | PA | Nonmetallic Mineral Product Manufacturing327331 | 1-19 | ◐ LIKELY ACTIVE |
| MIMae-eitel, INC | Orwigsburg | PA | Fabricated Metal Product Manufacturing332999 | 20-99 | ◐ LIKELY ACTIVE |
| MPMagee Plastics Company | Warrendale | PA | Plastics and Rubber Products Manufacturing326130 | 20-99 | ◐ LIKELY ACTIVE |
| MRMagnesita Refractories/york | York | PA | Food Manufacturing311119 | 100-499 | ◐ LIKELY ACTIVE |
| MCMaius Capital LLC | Glen Mills | PA | Food Manufacturing311213 | 1-19 | ◐ LIKELY ACTIVE |
Martin-baker America INC | Johnstown | PA | Transportation Equipment Manufacturing336413 | 100-499 | ◐ LIKELY ACTIVE |
Martin's Potato Chips, INC. | Thomasville | PA | Food Manufacturing311999 | 100-499 | ◐ LIKELY ACTIVE |
| MWMartins Wood Products/myerstown | Myerstown | PA | Furniture and Related Product Manufacturing337122 | 1-19 | ◐ LIKELY ACTIVE |
| MTMatrix Tool, INC. | Fairview | PA | Plastics and Rubber Products Manufacturing326199 | 100-499 | ◐ LIKELY ACTIVE |
| MWMaxwell Welding & Machine | Burgettstown | PA | Fabricated Metal Product Manufacturing332312 | 20-99 | ◐ LIKELY ACTIVE |
| MIMcc International, INC. | Mc Donald | PA | Primary Metal Manufacturing331513 | 20-99 | ◐ LIKELY ACTIVE |
| MLMccourt Label | Lewis Run | PA | Paper Manufacturing322299 | 20-99 | ◐ LIKELY ACTIVE |
| MCMclanahan CORP | Hollidaysburg | PA | Nonmetallic Mineral Product Manufacturing327400 | 100-499 | ◐ LIKELY ACTIVE |
| MFMeadville Forging Company - MFC | Meadville | PA | Fabricated Metal Product Manufacturing332111 | 100-499 | ◐ LIKELY ACTIVE |
| MIMedart, INC. | Ellwood City | PA | Machinery Manufacturing333519 | 20-99 | ◐ LIKELY ACTIVE |
Megaphase LLC | Stroudsburg | PA | Computer and Electronic Product Manufacturing334417 | 20-99 | ◐ LIKELY ACTIVE |
| MIMetalkraft Industries INC. | Wellsboro | PA | Fabricated Metal Product Manufacturing332117 | 20-99 | ◐ LIKELY ACTIVE |
| MSMichelman Steel Enterprises LLC | Bethlehem | PA | Fabricated Metal Product Manufacturing332312 | 20-99 | ◐ LIKELY ACTIVE |
| MTMicro Tool Company, INC. | Bethlehem | PA | Fabricated Metal Product Manufacturing332710 | 20-99 | ◐ LIKELY ACTIVE |
| MPMillet Plastics, INC. | Lebanon | PA | Plastics and Rubber Products Manufacturing326199 | 20-99 | ◐ LIKELY ACTIVE |
| MPMisco Products | Reading | PA | Chemical Manufacturing325611 | 100-499 | ◐ LIKELY ACTIVE |
| MFModel Finishing Co/phila | Philadelphia | PA | Fabricated Metal Product Manufacturing332999 | 1-19 | ◐ LIKELY ACTIVE |
| MGModerne Glass CO INC | Aliquippa | PA | Nonmetallic Mineral Product Manufacturing327215 | 100-499 | ◐ LIKELY ACTIVE |
| MModineer-pulverman | Dallas | PA | Fabricated Metal Product Manufacturing332322 | 100-499 | ◐ LIKELY ACTIVE |
| MPMonarch Products INC | York Haven | PA | Nonmetallic Mineral Product Manufacturing327390 | 20-99 | ◐ LIKELY ACTIVE |