| Portland Xpress Project Phase 1 (CAN to ME) | Portland Natural Gas Transmission System | ME, NH | In service 2018 | |
| Portland Xpress Project Phase 1 (ME to MA) | Portland Natural Gas Transmission System | MA, ME, NH | In service 2018 | |
| Poseidon Oil Pipeline coastal use permit P19961358 pipeline | Poseidon Oil Pipeline | LA | | |
| Post-CPX Send-Out Project | Dominion Cove Point LNG, LP | | | |
| Potomac Expansion Project | Transcontinental Gas Pipe Line Company, LLC | VA | In service 2007 | |
| Powderbowl Pipeline Project | Heavenly Valley, LP | | | |
| Praha Compressor Station | | TX | | |
| Prairie Rose Header Pipeline | Pecan Pipeline Co | ND | In service 2010 | |
| Pratt Compressor Upgrade | Equitrans, L.P. | PA, WV | In service 2010 | |
| Praxair coastal use permit P20090237 pipeline | Praxair, Inc | LA | | |
| Praxair coastal use permit P20111148 pipeline | Praxair, Inc | LA | | |
| Praxair coastal use permit P20161043 pipeline | Praxair, Inc | LA | | |
| Presidential Permit Amendmentt | Tennessee Gas Pipeline Company, L.L.C. | TX | | |
| Presidio Crossing Project | Trans-Pecos Pipeline, LLC | TX | 2016–2017 | |
| Princeton Lateral Project | Northern Border Pipeline Company | IL | 2011 | |
| ProLiance Energy Heartland Pipeline | ProLiance Energy LLC | IN | In service 2006 | |
| Progress Energy Wayne County | Piedmont Natural Gas | NC | 2011–2012 | |
| Project Wildcat | Enable Gas Transmission, LLC | OK, TX | In service 2018 | |
| Prometheus Pipeline | Rice Energy | OH | | |
| Proposed Line BKY Abandonment Project | Columbia Gas Transmission, LLC | WV | | |
| Proposed Terra Alta HP Upgrade Project | Columbia Gas Transmission, LLC | WV | | |
| Psi Midstream coastal use permit P20121299 pipeline | Psi Midstream, LLC | LA | | |
| Psi Midstream coastal use permit P20121572 pipeline | PSI Midstream Partners, LP | LA | | |
| Psi Midstream coastal use permit P20150497 pipeline | Psi Midstream, LLC | LA | | |
| Public Service Company of New Mexico CP09-25 | Public Service Company Of New Mexico | NM | | |
| Puget Sound Energy Jackson Prairie Storage Project | Puget Sound Energy | | | |
| Puget Sound Energy LNG Facility | Puget Sound Energy | WA | In service 2022 | |
| Pulaski Project | Columbia Gulf Transmission, LLC | KY | | |
| Pump Mesa Gathering System | | NM | | |
| Pump Station Additions - McKenzie & Dunn Counties | ONEOK Bakken Pipeline, L.L.C. | ND | | |