    <SEC-DOCUMENT>0001104659-21-045585-index.html : 20210401
    <SEC-HEADER>0001104659-21-045585.hdr.sgml : 20210401
    <ACCEPTANCE-DATETIME>20210401162203
    ACCESSION NUMBER:		0001104659-21-045585
    CONFORMED SUBMISSION TYPE:	DEFA14A
    PUBLIC DOCUMENT COUNT:		3
    FILED AS OF DATE:		20210401
    DATE AS OF CHANGE:		20210401

    FILER:

    	COMPANY DATA:
    		COMPANY CONFORMED NAME:			CORPORATE OFFICE PROPERTIES TRUST
    		CENTRAL INDEX KEY:			0000860546
    		STANDARD INDUSTRIAL CLASSIFICATION:	REAL ESTATE INVESTMENT TRUSTS [6798]
    		IRS NUMBER:				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:		21798397

    	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 INC
    		DATE OF NAME CHANGE:	19980105

    	FORMER COMPANY:
    		FORMER CONFORMED NAME:	ROYALE INVESTMENTS INC
    		DATE OF NAME CHANGE:	19930328

    	FORMER COMPANY:
    		FORMER CONFORMED NAME:	ROYALE REIT INC
    		DATE OF NAME CHANGE:	19600201
    </SEC-HEADER>
    <DOCUMENT>
    <TYPE>DEFA14A
    <SEQUENCE>1
    <FILENAME>tm212383d3_defa14a.htm
    <DESCRIPTION>DEFA14A
    <TEXT>
    Document 1 - file: tm212383d3_defa14a.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>2
    <FILENAME>tm212383d3_defa14aimg001.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 2 - file: tm212383d3_defa14aimg001.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>3
    <FILENAME>tm212383d3_defa14aimg002.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 3 - file: tm212383d3_defa14aimg002.jpg

    </DOCUMENT>
    </SEC-DOCUMENT>