| Cantium coastal use permit P20130602 pipeline | Cantium. LLC | LA | | |
| Cantium coastal use permit P20130603 pipeline | Cantium. LLC | LA | | |
| Cantium coastal use permit P20130604 pipeline | Cantium. LLC | LA | | |
| Cantium coastal use permit P20140707 pipeline | Cantium. LLC | LA | | |
| Cantium coastal use permit P20171077 pipeline | Cantium. LLC | LA | | |
| Cantium coastal use permit P20180784 pipeline | Cantium. LLC | LA | | |
| Canton Lateral Pipeline | Energy Transfer | PA | | |
| Canton Pipeline | SemGroup Corp | OK | In service 2017 | |
| Cape Cod Canal Bridge Relocation Project | Algonquin Gas Transmission, LLC | | | |
| Cape Cod Project | Algonquin Gas Transmission, LLC | MA | 2007 | |
| Capital Area Project | Eastern Gas Transmission and Storage, Inc. | PA, VA | | |
| Cardinal Pipeline | Transcontinental Gas Pipe Line Company, LLC | NC | In service 1999 | |
| Carlsbad Gateway Lea County Expansion Project | Carlsbad Gateway, LLC | NM, TX | Started 2024 | |
| Carlsbad South Project | El Paso Natural Gas Company, L.L.C. | NM, TX | In service 2021 | |
| Carnation Project | Texas Gas Transmission, LLC | OH | | |
| Carnero Dimmitt Extension | | TX | | |
| Carolina Market Link | Transcontinental Gas Pipe Line Company, LLC | NC | 2023–2024 | |
| Carpenter to Majorsville Pipeline | Markwest Liberty Midstream & Resources, LLC | WV | | |
| Carroll Connector Project | Dominion East Ohio Gas Company | OH | | |
| Carthage Junction Compressor Station Unit No. 7 Replacement | Gulf South Pipeline Company, LLC | TX | | |
| Carthage to Perryville Proj/Phase III Exp | Centerpoint Energy Gas Transmission | LA, TX | In service 2008 | |
| Carthage to Perryville Project | Centerpoint Energy Gas Transmission | LA, TX | In service 2008 | |
| Carty Lateral Project | Gas Transmission Northwest LLC | OR | 2015 | |
| Carver Compressor Station | | MN | | |
| Casey Creek Project | Columbia Gulf Transmission, LLC | KY | Started 2026 | |
| Cash to Haggard Pipeline | Eqt Production | WV | | |
| Casterly Rock Lateral | Eqt XL Midstream Operating LLC | WV | | |
| Castex Energy coastal use permit P20061824 pipeline | Castex Energy, Inc. | LA | | |
| Castex Energy coastal use permit P20120069 pipeline | Castex Energy, Inc. | LA | | |
| Castex Energy coastal use permit P20120199 pipeline | Castex Energy, Inc. | LA | | |