Ownership Submission
FORM 4
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
Matthews Louise E
  2. Issuer Name and Ticker or Trading Symbol
Summit Midstream Partners, LP [SMLP]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
See remarks below.
(Last)
(First)
(Middle)
C/O SUMMIT MIDSTREAM PARTNERS, LP, 1790 HUGHES LANDING BLVD., SUITE 500
3. Date of Earliest Transaction (Month/Day/Year)
03/15/2018
(Street)

THE WOODLANDS, TX 77380
4. If Amendment, Date Original Filed(Month/Day/Year)
6. Individual or Joint/Group Filing(Check Applicable Line)
_X_ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security
(Instr. 3)
2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code
(Instr. 8)
4. Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4 and 5)
5. Amount of Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 3 and 4)
6. Ownership Form: Direct (D) or Indirect (I)
(Instr. 4)
7. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V Amount (A) or (D) Price
Common Units 03/15/2018   M   7,881 A $ 0 16,059 D  
Common Units 03/15/2018   F   945 D $ 15.25 15,114 D  

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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 3)
2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 4. Transaction Code
(Instr. 8)
5. Number of Derivative Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4, and 5)
6. Date Exercisable and Expiration Date
(Month/Day/Year)
7. Title and Amount of Underlying Securities
(Instr. 3 and 4)
8. Price of Derivative Security
(Instr. 5)
9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 4)
10. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 4)
11. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares
Phantom Units (1) 03/15/2018   M     982   (2)   (3) Common Units 982 $ 0 0 D  
Distribution Equivalent Rights $ 6.885 03/15/2018   D     982   (2)   (3) Common Units 982 $ 0 0 D  
Phantom Units (1) 03/15/2018   M     3,936   (4)   (3) Common Units 3,936 $ 0 3,936 D  
Distribution Equivalent Rights $ 4.6 03/15/2018   D     3,936   (4)   (3) Common Units 3,936 $ 0 0 D  
Phantom Units (1) 03/15/2018   M     2,963   (5)   (3) Common Units 2,963 $ 0 5,925 D  
Distribution Equivalent Rights $ 2.3 03/15/2018   D     2,963   (5)   (3) Common Units 2,963 $ 0 0 D  
Phantom Units (1) 03/15/2018   A   14,098     (6)   (3) Common Units 14,098 $ 0 14,098 D  

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
Matthews Louise E
C/O SUMMIT MIDSTREAM PARTNERS, LP
1790 HUGHES LANDING BLVD., SUITE 500
THE WOODLANDS, TX 77380
      See remarks below.  

Signatures

 /s/ Brock M. Degeyter, Attorney-in-Fact for Louise E. Matthews   03/16/2018
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1) Each phantom unit is the economic equivalent of one common unit.
(2) The final one-third of the phantom units subject to the original award agreement vested on March 15, 2018, on the third anniversary of the March 15, 2015 grant date. The Reporting Person received distribution equivalent rights (DERs) for each phantom unit, providing for payment on the vesting date of a lump sum of cash equal to the accrued distributions from and after the grant date of the phantom units.
(3) The phantom units and associated DERs do not expire. The phantom units are settled upon vesting in common units (on a one-for-one basis) or in cash, at the discretion of the Issuer.
(4) One-third of the phantom units subject to the original award agreement vested on March 15, 2018, with the final one-third of the phantom units subject to vesting on the third anniversary of the March 15, 2016 grant date, subject to continued employment. The Reporting Person received distribution equivalent rights (DERs) for each phantom unit, providing for payment on the vesting date of a lump sum of cash equal to the accrued distributions from and after the grant date of the phantom units.
(5) One-third of the phantom units subject to the original award agreement vested on March 15, 2018, with the remaining phantom units subject to vesting on the second and third anniversaries of the March 15, 2017 grant date, subject to continued employment. The Reporting Person received DERs for each phantom unit, providing for payment on the vesting date of a lump sum of cash equal to the accrued distributions from and after the grant date of the phantom units.
(6) One-third of the phantom units (rounded down to the nearest whole number of units, except in the case of the final vesting date) shall vest on each of the first, second and third anniversaries of the Grant Date (March 15, 2018), subject to continued employment and accelerated vesting as provided in the applicable award agreement. The Reporting Person will receive distribution equivalent rights for each phantom unit, providing for payment on the vesting date of a lump sum of cash equal to the accrued distributions from and after the grant date of the phantom units.
 
Remarks:
The Reporting Person is Vice President - Human Resources and Corporate Communications of Summit Midstream GP, LLC, the general partner of the Issuer (the "General Partner"). The Issuer is managed by the directors and executive officers of the General Partner.

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