| KMKerotest Manufacturing Corp. Pittsburgh, PA | Pittsburgh | PA | Fabricated Metal Product Manufacturing332911 | 20-99 | ◐ LIKELY ACTIVE |
| KCKeystone Cement CO | Bath | PA | Nonmetallic Mineral Product Manufacturing327310 | — | ◐ LIKELY ACTIVE |
| KCKeystone Conemaugh Proj Llc/conemaugh Station | New Florence | PA | Chemical Manufacturing325520 | — | ◐ LIKELY ACTIVE |
| KFKeystone Foundry Div | Erie | PA | Primary Metal Manufacturing331529 | — | ◐ LIKELY ACTIVE |
| KIKeystone Industries | Myerstown | PA | Miscellaneous Manufacturing339112 | — | ◐ LIKELY ACTIVE |
| KLKeystone Leather Distr/williamsport Reach Rd Plt | Williamsport | PA | Leather and Allied Product Manufacturing316990 | 1-19 | ◐ LIKELY ACTIVE |
| KSKeystone Sheets LLC | Chambersburg | PA | Paper Manufacturing322211 | 100-499 | ◐ LIKELY ACTIVE |
| KCKh Controls INC | Blairsville | PA | Electrical Equipment, Appliance & Component Manufacturing335999 | 20-99 | ◐ LIKELY ACTIVE |
| KLK & L Woodworking/reading Facility | Reading | PA | Furniture and Related Product Manufacturing337212 | 1-19 | ◐ LIKELY ACTIVE |
| KIKnoll INC - East Greenville Plant | East Greenville | PA | Textile Product Mills314110 | — | ◐ LIKELY ACTIVE |
| KFKnouse Foods, INC. | Peach Glen | PA | Food Manufacturing311421 | 100-499 | ◐ LIKELY ACTIVE |
| KMKRB Machinery | Wrightsville | PA | Machinery Manufacturing333120 | 20-99 | ◐ LIKELY ACTIVE |
| KTKruse Tool & Die INC | Warminster | PA | Machinery Manufacturing333511 | 20-99 | ◐ LIKELY ACTIVE |
| KRKymera Reading Alloys Inc/robesonia | Robesonia | PA | Primary Metal Manufacturing331112 | 100-499 | ◐ LIKELY ACTIVE |
| LILaminators inc | Hatfield | PA | Fabricated Metal Product Manufacturing332311 | 20-99 | ◐ LIKELY ACTIVE |
| LLLancaster Leaf Tobacco CO of Pa INC | Lancaster | PA | Beverage and Tobacco Product Manufacturing312210 | 100-499 | ◐ LIKELY ACTIVE |
| LPLasko Products, INC. | West Chester | PA | Machinery Manufacturing333412 | 500+ | ◐ LIKELY ACTIVE |
| LSLatrobe Spec Steel Sandycreek Svc Ctr | Franklin | PA | Primary Metal Manufacturing331110 | — | ◐ LIKELY ACTIVE |
| LTLeading Technologies INC | Leechburg | PA | Fabricated Metal Product Manufacturing332812 | — | ◐ LIKELY ACTIVE |
Lebanon Machine & Manufacturing CO LLC | Lebanon | PA | Fabricated Metal Product Manufacturing332710 | 1-19 | ◐ LIKELY ACTIVE |
| LVLebanon Valley Aluminum | Lebanon | PA | Plastics and Rubber Products Manufacturing326291 | — | ◐ LIKELY ACTIVE |
| LCLeech Carbide | Meadville | PA | Fabricated Metal Product Manufacturing332117 | 20-99 | ◐ LIKELY ACTIVE |
| LTLeefson Tool & Die CO | Folcroft | PA | Fabricated Metal Product Manufacturing332119 | 1-19 | ◐ LIKELY ACTIVE |
| LOLee's Oriental Gourmet Foods | Shenandoah | PA | Food Manufacturing311612 | 20-99 | ◐ LIKELY ACTIVE |
| LCLehigh Cement CO LLC | York | PA | Nonmetallic Mineral Product Manufacturing327310 | — | ◐ LIKELY ACTIVE |
| LSLehigh Specialty Melting INC | Latrobe | PA | Primary Metal Manufacturing331110 | — | ◐ LIKELY ACTIVE |
| LVLehigh Valley Dairies | Schuylkill Haven | PA | Food Manufacturing311511 | — | ◐ LIKELY ACTIVE |
| LDLeiby's Dairy Inc | Tamaqua | PA | Food Manufacturing311520 | 20-99 | ◐ LIKELY ACTIVE |
Lenox Instrument Co., INC. | Feasterville Trevose | PA | Computer and Electronic Product Manufacturing334513 | 1-19 | ◐ LIKELY ACTIVE |
| LPLesleh Precision INC | Rostraver Township | PA | Fabricated Metal Product Manufacturing332710 | — | ◐ LIKELY ACTIVE |
| LCLiberty Coating Company LLC | Morrisville | PA | Fabricated Metal Product Manufacturing332812 | 20-99 | ◐ LIKELY ACTIVE |
| LSLittell Steel Company, Inc. | New Brighton | PA | Fabricated Metal Product Manufacturing332312 | 20-99 | ◐ LIKELY ACTIVE |
| LFL&m Fabrication & Machine Inc/ East Allen | Bath | PA | Fabricated Metal Product Manufacturing332312 | — | ◐ LIKELY ACTIVE |
| LCLord Corp/erie | Erie | PA | Textile Mills313320 | 500+ | ◐ LIKELY ACTIVE |
| LCLord Corporation - Saegertown Operations | Saegertown | PA | Chemical Manufacturing325320 | — | ◐ LIKELY ACTIVE |
Luzerne Optical Laboratories LTD | Wilkes Barre | PA | Miscellaneous Manufacturing339115 | 100-499 | ◐ LIKELY ACTIVE |
| LELycoming Engines/oliver St Plt | Williamsport | PA | Transportation Equipment Manufacturing336412 | — | ◐ LIKELY ACTIVE |
| MMMachined Metals Manufacturing | Collegeville | PA | Machinery Manufacturing333517 | 20-99 | ◐ LIKELY ACTIVE |
| MCMachining Concepts Inc. | Erie | PA | Fabricated Metal Product Manufacturing332710 | 20-99 | ◐ LIKELY ACTIVE |
| MTMachining Technology INC. | Hazle Township | PA | Fabricated Metal Product Manufacturing332721 | 1-19 | ◐ LIKELY ACTIVE |
| MTMack Trucks Inc/macungie | Macungie | PA | Transportation Equipment Manufacturing336120 | — | ◐ LIKELY ACTIVE |
| MTMack Trucks Inc/remanufacturing Ctr | Middletown | PA | Fabricated Metal Product Manufacturing332439 | — | ◐ LIKELY ACTIVE |
| MSMain Steel Inc/harmony | Harmony | PA | Fabricated Metal Product Manufacturing332117 | — | ◐ LIKELY ACTIVE |
| MMMal-ber Manufacturing CO. | Huntingdon Valley | PA | Fabricated Metal Product Manufacturing332710 | 1-19 | ◐ LIKELY ACTIVE |
| MEMarkovitz Enterprises | Zelienople | PA | Fabricated Metal Product Manufacturing332999 | 20-99 | ◐ LIKELY ACTIVE |
Martin's Furniture, LLC | Ephrata | PA | Furniture and Related Product Manufacturing337122 | 1-19 | ◐ LIKELY ACTIVE |
| MBMaster Builders Solutions Const Sys Bristol Plt | Levittown | PA | Chemical Manufacturing325510 | — | ◐ LIKELY ACTIVE |
| MWMaster Woodcraft/washington Plt | Washington | PA | Furniture and Related Product Manufacturing337110 | 20-99 | ◐ LIKELY ACTIVE |
| MBMaterion Brush INC | Shoemakersville | PA | Primary Metal Manufacturing331410 | — | ◐ LIKELY ACTIVE |
Max Ta Group LLC | Sharpsville | PA | Transportation Equipment Manufacturing336992 | — | ◐ LIKELY ACTIVE |