First Supplemental Indenture, dated as of January 5, 2022, by and between the Partnership and U.S. Bank, National Association, with respect to the Partnerships Indenture dated December 1, 1993 related to the Partnerships 7.48% Debentures due August 15, 2026 and 6.82% Medium Term Notes due August 1, 2027

Exhibit 4.1

FIRST SUPPLEMENTAL INDENTURE

This First Supplemental Indenture (this “Supplemental Indenture”), dated as of January 5, 2022, among Federal Realty OP LP, a Delaware limited partnership (the “Company”), and U.S. Bank National Association, as trustee under the Indenture referred to below (the “Trustee”).

BACKGROUND

A. The Company, formerly known as Federal Realty Investment Trust, a Maryland real estate investment trust, has undertaken a reorganization (the “Reorganization”) pursuant to which:

B. The Company and the Trustee are parties to that certain Indenture dated as of December 1, 1993 (the “Indenture”).

C. The Reorganization is permitted by the Indenture, including Section 801 thereof, without the consent of the Holders, and the Company will deliver to the Trustee an Officers’ Certificate and Opinion of Counsel to that effect.

D. In connection with the Reorganization, the Company and the Trustee desire to enter into this Supplemental Indenture pursuant to Section 901(9) of the Indenture, which provides that, without the consent of any Holders of Securities or coupons, the Company, when authorized by or pursuant to a Board Resolution, and the Trustee, at any time and from time to time, may enter into one or more indentures supplemental to the Indenture, in form satisfactory to the Trustee, to cure any ambiguity or to correct defective provisions therein.

AGREEMENT

NOW, THEREFORE, for good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the Company and the Trustee hereby agree as follows:

1. Usage of Terms. Effective immediately following the effectiveness of the Conversion, on the date of this Supplemental Indenture, to cure an ambiguity resulting therefrom:

2. Capitalized Terms. Capitalized terms used but not defined herein shall have the meanings given to them in the Indenture.

3. Governing Law. This Supplemental Indenture shall be governed by and construed in accordance with the law of the State of New York.

4. Counterparts. The parties may sign any number of copies of this Supplemental Indenture. Each signed copy shall be an original, but all of them together represent the same agreement.

5. The Trustee. The Trustee shall not be responsible in any manner whatsoever for or in respect of the validity or sufficiency of this Supplemental Indenture or for or in respect of the recitals contained herein, all of which recitals are made solely by the Company.

[Signature Page Follows]

2

IN WITNESS WHEREOF, the parties hereto have caused this First Supplemental Indenture to be duly executed and attested, all as of the date first above written.

First Supplemental Indenture – 1993 Indenture