    <SEC-DOCUMENT>0000860546-25-000016-index.html : 20250331
    <SEC-HEADER>0000860546-25-000016.hdr.sgml : 20250331
    <ACCEPTANCE-DATETIME>20250331153047
    ACCESSION NUMBER:		0000860546-25-000016
    CONFORMED SUBMISSION TYPE:	DEFA14A
    PUBLIC DOCUMENT COUNT:		4
    FILED AS OF DATE:		20250331
    DATE AS OF CHANGE:		20250331

    FILER:

    	COMPANY DATA:
    		COMPANY CONFORMED NAME:			COPT DEFENSE PROPERTIES
    		CENTRAL INDEX KEY:			0000860546
    		STANDARD INDUSTRIAL CLASSIFICATION:	REAL ESTATE INVESTMENT TRUSTS [6798]
    		ORGANIZATION NAME:           	05 Real Estate & Construction
    		EIN:				232947217
    		STATE OF INCORPORATION:			MD
    		FISCAL YEAR END:			1231

    	FILING VALUES:
    		FORM TYPE:		DEFA14A
    		SEC ACT:		1934 Act
    		SEC FILE NUMBER:	001-14023
    		FILM NUMBER:		25792644

    	BUSINESS ADDRESS:
    		STREET 1:		6711 COLUMBIA GATEWAY DRIVE
    		STREET 2:		SUITE 300
    		CITY:			COLUMBIA
    		STATE:			MD
    		ZIP:			21046
    		BUSINESS PHONE:		4432855400

    	MAIL ADDRESS:
    		STREET 1:		6711 COLUMBIA GATEWAY DRIVE
    		STREET 2:		SUITE 300
    		CITY:			COLUMBIA
    		STATE:			MD
    		ZIP:			21046

    	FORMER COMPANY:
    		FORMER CONFORMED NAME:	CORPORATE OFFICE PROPERTIES TRUST
    		DATE OF NAME CHANGE:	19980514

    	FORMER COMPANY:
    		FORMER CONFORMED NAME:	CORPORATE OFFICE PROPERTIES TRUST INC
    		DATE OF NAME CHANGE:	19980105

    	FORMER COMPANY:
    		FORMER CONFORMED NAME:	ROYALE INVESTMENTS INC
    		DATE OF NAME CHANGE:	19930328
    </SEC-HEADER>
    <DOCUMENT>
    <TYPE>DEFA14A
    <SEQUENCE>1
    <FILENAME>a2025cdpproxy-additionalso.htm
    <DESCRIPTION>DEFA14A
    <TEXT>
    Document 1 - file: a2025cdpproxy-additionalso.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>2
    <FILENAME>coptdefenseproperties_vxau.jpg
    <TEXT>
    Document 2 - file: coptdefenseproperties_vxau.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>3
    <FILENAME>coptdefenseproperties_vxaua.jpg
    <TEXT>
    Document 3 - file: coptdefenseproperties_vxaua.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>4
    <FILENAME>coptmain.jpg
    <TEXT>
    Document 4 - file: coptmain.jpg

    </DOCUMENT>
    </SEC-DOCUMENT>