Washington, D.C. 20549

OMB Number: 3235-0104
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Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940
1. Name and Address of Reporting Person * TTC Holdings LLC 2. Date of Event Requiring Statement (MM/DD/YYYY)

3. Issuer Name and Ticker or Trading Symbol MPLX LP [MPLX]
(Last)       (First)       (Middle)
4. Relationship of Reporting Person(s) to Issuer (Check all applicable)_____ Director                          ___X___ 10% Owner
_____ Officer (give title below)        _____ Other (specify below)
FINDLAY, OH 45840      
(City)             (State)             (Zip)
5. If Amendment, Date Original Filed(MM/DD/YYYY)

6. Individual or Joint/Group Filing(Check Applicable Line)_X_ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Beneficially Owned
1.Title of Security
(Instr. 4)
2. Amount of Securities Beneficially Owned
(Instr. 4)
3. Ownership Form: Direct (D) or Indirect (I)
(Instr. 5)
4. Nature of Indirect Beneficial Ownership
(Instr. 5)
Common Units (Limited Partner Interests)  647415452  I  See Footnotes (1)(2)(3)(4)
TexNew Mex Units  80000  I  See Footnotes (1)(2)(3)(4)
Special Limited Partner Interest  1  I  See Footnotes (1)(2)(3)(4)

Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivate Security
(Instr. 4)
2. Date Exercisable and Expiration Date
3. Title and Amount of Securities Underlying Derivative Security
(Instr. 4)
4. Conversion or Exercise Price of Derivative Security 5. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 5)
6. Nature of Indirect Beneficial Ownership
(Instr. 5)
Date Exercisable Expiration Date Title Amount or Number of Shares

Explanation of Responses:
(1)  This Form 3 is submitted by TTC Holdings LLC ("TTC Holdings") which, effective as of January 1, 2021 (the "Effective Date"), and pursuant to the Reorganization Agreement, dated as of December 31, 2020 (the "Reorganization Agreement"), by and among TTC Holdings, Andeavor LLC, Western Refining, Inc. ("WRI"), Giant Industries, Inc. ("GII"), Western Refining Southwest, Inc. ("WRSI"), Tesoro Refining & Marketing Company LLC ("TRMC"), Tesoro Alaska Company LLC ("TAC"), Tesoro Logistics GP, LLC ("TLGP"), and the other signatories thereto, became a part of the reporting group which includes Marathon Petroleum Corporation ("MPC"), MPC Investment LLC ("MPC Investment"), MPLX GP LLC (the "General Partner"), MPLX Logistics Holdings LLC ("Logistics Holdings"), Andeavor LLC, WRI and GII.
(2)  MPC Investment, a direct wholly-owned subsidiary of MPC, owns all of the membership interests in the General Partner and Logistics Holdings. Andeavor LLC is a wholly owned subsidiary of MPC. WRI is a wholly owned subsidiary of Andeavor LLC. TTC Holdings is a wholly owned subsidiary WRI. GII is a wholly owned subsidiary of TTC Holdings. Accordingly, MPC Investment, the General Partner, Logistics Holdings, Andeavor LLC, WRI, TTC Holdings and GII are all direct or indirect wholly owned subsidiaries of MPC.
(3)  The Reorganization Agreement sets forth a series of intercompany transactions pursuant to which, among other things: (i) TRMC and TAC distributed to WRSI all of the outstanding limited liability company interests in TLGP held by each of TRMC and TAC immediately prior to such distribution; (ii) TLGP distributed to WRSI all of the common units representing limited partner interests in the Issuer held by TLGP prior to such distribution; (iii) WRSI converted to a Delaware limited liability company under the name Western Refining Southwest LLC ("WRSWL"); (iv) WRSWL distributed to GII all of the (x) common units representing limited partner interests in the Issuer, (y) MPLX TexNew Mex units and (z) the MPLX Special Limited Partner Interest held, in each case, by WRSWL immediately prior to such distribution (collectively, the "MPLX Interests"); and (v) WRI contributed all of the outstanding capital stock of GII to TTC Holdings.
(4)  TTC Holdings may be deemed to beneficially own the MPLX Interests owned by GII but disclaims beneficial ownership of such securities except to the extent of its pecuniary interest therein.

Reporting Owners
Reporting Owner Name / Address
Director 10% Owner Officer Other
TTC Holdings LLC


/s/ Molly R. Benson, Vice President and Secretary, TTC Holdings LLC 1/8/2021
**Signature of Reporting Person Date
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