Take notice that on May 15, 2026, Rockies Express Pipeline LLC (REX), 11550 Ash Street, Suite 220, Leawood, Kansas 66211, filed supplemental information in Docket No. CP25-539-000. The Commission is treating this filing as an amendment to REX's application in Docket No. CP25-539-000 pursuant to sections 7(b) and 7(c) of the Natural Gas Act (NGA) and Part 157 of the Commission's regulations, and hereby gives notice of the proposed amendment. Specifically, REX is amending its Critical Energy Reliability Link Project (Project) by adding: (1) the Williams Creek Spur, a 1.6-mile-long, 24-inch-diameter pipeline, extending from Milepost 148.4 of its proposed Lateral to an interconnection with the future Williams Creek Generation Station, (2) the Williams Creek Meter Station at the terminus of the Willams Creek Spur, and (3) associated appurtenant facilities, all located in El Paso County, Colorado. Additionally, REX reroutes various segments of its proposed Lateral in Colorado, increasing the overall length by 1.1 miles, and restates the proposed horsepower at the proposed LaSalle Compressor Station in Weld County, Colorado as 6,300 horsepower.^[1] REX states that the proposed modifications will not result in any change to the Project capacity, all as more fully set forth in the amendment to application which is on file with the Commission and open for public inspection.

In addition to publishing the full text of this document in the Federal Register , the Commission provides all interested persons an opportunity to view and/or print the contents of this document via the internet through the Commission's Home Page ( http://www.ferc.gov). From the Commission's Home Page on the internet, this information is available on eLibrary. The full text of this document is available on eLibrary in PDF and Microsoft Word format for viewing, printing, and/or downloading. To access this document in eLibrary, type the docket number excluding the last three digits of this document in the docket number field.

User assistance is available for eLibrary and the Commission's website during normal business hours from FERC Online Support at (202) 502-6652 (toll free at 1-866-208-3676) or email at ferconlinesupport@ferc.gov, or the Public Reference Room at (202) 502-8371, TTY (202) 502-8659. Email the Public Reference Room at public.referenceroom@ferc.gov.

Any questions regarding the proposed Project should be directed to Eryn Pullin, Manager, Regulatory Affairs, Tallgrass Energy, LP, 9 Greenway Plaza, Suite 1100, Houston, Texas 77046, by phone at (713) 997-3932, or by email at eryn.pullin@tallgrass.com.

Pursuant to section 157.9 of the Commission's Rules of Practice and Procedure,^[2] within 90 days of this Notice the Commission staff will either: complete its environmental review and place it into the Commission's public record (eLibrary) for this proceeding; or issue a Notice of Schedule for Environmental Review. If a Notice of Schedule for Environmental Review is issued, it will indicate, among other milestones, the anticipated date for the Commission staff's issuance of the final environmental impact statement (FEIS) or environmental assessment (EA) for this proposal. The filing of an EA in the Commission's public record for this proceeding or the issuance of a Notice of Schedule for Environmental Review will serve to notify federal and state agencies of the timing for the completion of all necessary reviews, and the subsequent need to complete all federal authorizations within 90 days of the date of issuance of the Commission staff's FEIS or EA.

Public Participation

There are three ways to become involved in the Commission's review of this project: you can file comments on the project, you can protest the filing, and you can file a motion to intervene in the proceeding. There is no fee or cost for filing comments or intervening. The deadline for filing a motion to intervene is 5:00 p.m. Eastern Time on June 12, 2026. How to file protests, motions to intervene, and comments is explained below.

For public inquiries and assistance with making filings such as interventions, comments, or requests for rehearing, contact the Office of Public Participation (OPP) at (202) 502-6595 or OPP@ferc.gov.

Comments

Any person wishing to comment on the project may do so. Comments may include statements of support or objections, to the project as a whole or specific aspects of the project. The more specific your comments, the more useful they will be.

Protests

Pursuant to sections 157.10(a)(4) ^[3] and 385.211 ^[4] of the Commission's regulations under the NGA, any person ^[5] may file a protest to the application. Protests must comply with the requirements specified in section 385.2001 ^[6] of the Commission's regulations. A protest may also serve as a motion to intervene so long as the protestor states it also seeks to be an intervenor.

To ensure that your comments or protests are timely and properly recorded, please submit your comments on or before 5:00 p.m. Eastern Time on June 12, 2026.

There are three methods you can use to submit your comments or protests to the Commission. In all instances, please reference the Project docket numbers CP25-539-001 and CP25-539-000 in your submission.

(1) You may file your comments electronically by using the eComment feature, which is located on the Commission's website at www.ferc.gov under the link to Documents and Filings. Using eComment is an easy method for interested persons to submit brief, text-only comments on a project;

(2) You may file your comments or protests electronically by using the eFiling feature, which is located on the Commission's website ( www.ferc.gov) under the link to Documents and Filings. With eFiling, you can provide comments in a variety of formats by attaching them as a file with your submission. New eFiling users must first create an account by clicking on “eRegister.” You will be asked to select the type of filing you are making; first select “General” and then select “Comment on a Filing”; or

(3) You can file a paper copy of your comments or protests by mailing them to the following address below. Your written comments must reference the Project docket numbers (CP25-539-001 and CP25-539-000).

To file via USPS: Debbie-Anne A. Reese, Secretary, Federal Energy ( printed page 32045) Regulatory Commission, 888 First Street NE, Washington, DC 20426.

To file via any other courier: Debbie-Anne A. Reese, Secretary, Federal Energy Regulatory Commission, 12225 Wilkins Avenue, Rockville, Maryland 20852.

The Commission encourages electronic filing of comments (options 1 and 2 above) and has eFiling staff available to assist you at (202) 502-8258 or FercOnlineSupport@ferc.gov.

Persons who comment on the environmental review of this project will be placed on the Commission's environmental mailing list, and will receive notification when the environmental documents (EA or EIS) are issued for this project and will be notified of meetings associated with the Commission's environmental review process.

The Commission considers all comments received about the project in determining the appropriate action to be taken. However, the filing of a comment alone will not serve to make the filer a party to the proceeding. To become a party, you must intervene in the proceeding. For instructions on how to intervene, see below.

Interventions

Any person, which includes individuals, organizations, businesses, municipalities, and other entities,^[7] has the option to file a motion to intervene in this proceeding. Only intervenors have the right to request rehearing of Commission orders issued in this proceeding and to subsequently challenge the Commission's orders in the U.S. Circuit Courts of Appeal.

To intervene, you must submit a motion to intervene to the Commission in accordance with Rule 214 of the Commission's Rules of Practice and Procedure ^[8] and the regulations under the NGA ^[9] by the intervention deadline for the project, which is 5:00 p.m. Eastern Time on June 12, 2026. As described further in Rule 214, your motion to intervene must state, to the extent known, your position regarding the proceeding, as well as your interest in the proceeding. For an individual, this could include your status as a landowner, ratepayer, resident of an impacted community, or recreationist. You do not need to have property directly impacted by the project in order to intervene. For more information about motions to intervene, refer to the FERC website at https://www.ferc.gov/​resources/​guides/​how-to/​intervene.asp.

There are two ways to submit your motion to intervene. In both instances, please reference the Project docket numbers CP25-539-001 and CP25-539-000 in your submission.

(1) You may file your motion to intervene by using the Commission's eFiling feature, which is located on the Commission's website ( www.ferc.gov) under the link to Documents and Filings. New eFiling users must first create an account by clicking on “eRegister.” You will be asked to select the type of filing you are making; first select “General” and then select “Intervention.” The eFiling feature includes a document-less intervention option; for more information, visit https://www.ferc.gov/​docs-filing/​efiling/​document-less-intervention.pdf.; or

(2) You can file a paper copy of your motion to intervene, along with three copies, by mailing the documents to the address below. Your motion to intervene must reference the Project docket numbers CP25-539-001 and CP25-539-000.

To file via USPS: Debbie-Anne A. Reese, Secretary, Federal Energy Regulatory Commission, 888 First Street NE, Washington, DC 20426.

To file via any other courier: Debbie-Anne A. Reese, Secretary, Federal Energy Regulatory Commission, 12225 Wilkins Avenue, Rockville, Maryland 20852.

The Commission encourages electronic filing of motions to intervene (option 1 above) and has eFiling staff available to assist you at (202) 502-8258 or FercOnlineSupport@ferc.gov.

Protests and motions to intervene must be served on the applicant either by mail at: Eryn Pullin, Manager, Regulatory Affairs, Tallgrass Energy, LP, 9 Greenway Plaza, Suite 1100, Houston, Texas 77046 or by email (with a link to the document) at eryn.pullin@tallgrass.com. Any subsequent submissions by an intervenor must be served on the applicant and all other parties to the proceeding. Contact information for parties can be downloaded from the service list at the eService link on FERC Online. Service can be via email with a link to the document.

All timely, unopposed ^[10] motions to intervene are automatically granted by operation of Rule 214(c)(1).^[11] Motions to intervene that are filed after the intervention deadline are untimely, and may be denied. Any late-filed motion to intervene must show good cause for being late and must explain why the time limitation should be waived and provide justification by reference to factors set forth in Rule 214(d) of the Commission's Rules and Regulations.^[12] A person obtaining party status will be placed on the service list maintained by the Secretary of the Commission and will receive copies (paper or electronic) of all documents filed by the applicant and by all other parties.

Tracking the Proceeding

Throughout the proceeding, additional information about the project will be available from OPP at (202) 502-6595 or on the FERC website at www.ferc.gov using the “eLibrary” link as described above. The eLibrary link also provides access to the texts of all formal documents issued by the Commission, such as orders, notices, and rulemakings.

In addition, the Commission offers a free service called eSubscription which allows you to keep track of all formal issuances and submittals in specific dockets. This can reduce the amount of time you spend researching proceedings by automatically providing you with notification of these filings, document summaries, and direct links to the documents.

For more information and to register, go to www.ferc.gov/​docs-filing/​esubscription.asp.

Intervention Deadline: 5:00 p.m. Eastern Time on June 12, 2026.

(Authority: 18 CFR 2.1.)