245 Summer Street

Fidelity® Investments

Boston, MA 02210

November 27, 2024

U.S. Securities & Exchange Commission

100 F Street, N.E.

Washington, D.C. 20549

RE: Fidelity Hereford Street Trust (the trust): File Nos. 033-52577 and 811-07139 Fidelity Treasury Only Money Market Fund (the fund(s)) Post-Effective Amendment No. __71__

________________________________________________________________________

Ladies and Gentlemen:

Pursuant to Rule 8b-16 under the Investment Company Act of 1940, as amended, Regulation S-T and Rule 485(a) under the Securities Act of 1933, as amended, (33 Act) transmitted herewith on behalf of the trust is Post-Effective Amendment No. 71 to the trust’s current effective Registration Statement on Form N-1A.  This transmission contains a conformed signature page, the manually signed original of which is maintained at the offices of the trust.

 The principal purpose of this filing is to register a new class for the fund: Class OUS for Fidelity Treasury Only Money Market Fund.

This filing contains the Prospectus(es) and Statement(s) of Additional Information for the fund(s) referenced above.

Please note that the cover page of the Prospectus(es) and SAI(s) contain the standard “red herring” legend called for by Rule 481 of Regulation C.

Pursuant to Rule 485(a), the trust elects an effective date of January 27, 2025. We request your comments by January 6, 2025.

Please contact Renée Fuller at (603) 721-4221 with any questions or comments regarding this filing.

Sincerely,

/s/Renée Fuller

Renée Fuller

Shareholder Reporting