| Clifton to Palmyra A-line Abandonment Project | Northern Natural Gas Company | KS, NE | 2021 | |
| Clint Export Project | Oasis Pipeline LP | TX | | |
| Clinton Town Border and Pipeline ES Relocation Project | Southern Star Central Gas Pipeline, Inc. | | | |
| Clover Valley Pipeline Project | National Gas & Oil Cooperative | OH | Started 2025 | |
| Coastal Bend Header | Boardwalk Pipeline Partners | TX | 2017–2018 | |
| Coastal Bend Header Project | Gulf South Pipeline Company, LLC | TX | | |
| Coastal Bend LNG Project | Coastal Bend LNG Development LLC | TX | | |
| Coastal States Tradi coastal use permit P19971559 pipeline | Coastal States Tradi | LA | | |
| Cobb Compressor Station | Columbia Gas Transmission, LLC | WV | | |
| Cochin Marcellus Lateral Pipeline | | OH | | |
| Coco B Wells Replacement Project | Columbia Gas Transmission, LLC | WV | 2023–2024 | |
| Coco Compressor Station Replacement | Columbia Gas Transmission, LLC | WV | | |
| Coden Onshore Pipeline | Freeport-McMoRan Energy LLC | AL | | |
| Cogent Residue Pipeline | Cogent Midstream | TX | | |
| Cole to Breon Connector | | PA | | |
| Coleman Compressor Engine Upgrade Project | Questar Pipeline | WY | In service 2014 | |
| Collierville Compressor Station | | TN | In service 2017 | |
| Collins Pipeline coastal use permit P20020031 pipeline | Collins Pipeline Co | LA | | |
| Collins Pipeline coastal use permit P20031621 pipeline | Collins Pipeline Co | LA | | |
| Collins Pipeline coastal use permit P20210261 pipeline | Collins Pipeline Co | LA | | |
| Collins Pipeline coastal use permit P20210641 pipeline | Collins Pipeline Co | LA | | |
| Colonial Pipeline 16-inch Pipeline, Hamilton, Bradley and McMinn Counties, TN | Colonial Pipeline Company | TN | | |
| Colonial Pipeline coastal use permit P19960555 pipeline | Colonial Pipeline Co | LA | | |
| Colonial Pipeline coastal use permit P20141661 pipeline | Colonial Pipeline Co | LA | | |
| Colonial Pipeline coastal use permit P20150650 pipeline | Colonial Pipeline Co | LA | | |
| Colorado Hub Connection Project | Northwest Pipeline GP | CO | 2009 | |
| Colorado Interstate Gas CP03-7 | Colorado Interstate Gas Company, L.L.C. | CO | | |
| Colorado Interstate Gas PF06-36 | Colorado Interstate Gas Company, L.L.C. | | | |
| Columbia Gas Galloway Road OPSB case 99-0585-GA-BLN | Columbia Gas | OH | | |
| Columbia Gas Rohr Road OPSB case 99-0735-GA-BLN | Columbia Gas | OH | | |